# Giant mulch rings...never seen one, and don't believe in them!



## pdqdl (May 31, 2009)

Every time someone mentions lawn and trees in the same breath (here at ArboristSite), someone always seems to pipe in with the comment to add mulch out to the dripline.

Sorry, I simply don't get it.

Kansas City is FILLED with trees. We fight them like weeds. If you don't pay attention, in 15 years, you don't have a lawn, you have a forest. At least 1/2 of the tree work we get is removing trees that never should have been where they ended up growing.

We have heavy clay soil (Clay County, in fact!), rich bottom land with perfect soil, and we have our share of sandy soil and gravel/rocky soil. Sorry, no flint or granite soils here, everything is limestone.

I have never seen a tree killed off by the lawn, and I have never seen a mature tree mulched to the dripline, either.

I can look down _*every single*_ street in this town and point out where the larger trees have killed off the lawn: bare dirt beneath them. In fact, nearly every homeowner in town is aware of this single, compelling fact: Too many trees, and you won't have any lawn. Period.

WHY do you folks keep telling us to increase the mulch ring to protect the tree from the lawn? 

Is Kansas City a tree oasis, where trees thrive better than elsewhere? I have always considered trees the "apex predator" of the plant kingdom. Please tell me where I have it wrong!

I promise to listen carefully, but only to compelling, thoughtful, and well documented arguments.


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## chewbacca (May 31, 2009)

You make a compelling point. I am from Ohio. I now live in north Idaho. Climate and soil profile are drastically different in those two areas. Large deciduous trees do well in ohio. They naturally have what they need there (for the most part). Here in idaho, they are not native. We have very dry summers and we have to irrigate anything we plant that is not native. Because of that fact alone (and maybe others), trees benefit from not having to compete for water with lawn. You're absolutely right. Every situation is different and should be examined closely. In the world of arboriculture (and other fields too - I'm sure), a notion becomes popular and almost becomes law. To the point where anyone who doesn't follow suit is looked down upon. Some people take themselves way too seriously. If the benefits gained from mulching trees don't outweigh the costs (in your experience), don't do it. Can't worry about what everyone else thinks. Cheers


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## outofmytree (May 31, 2009)

I know what you mean pdqdl. I have seen only a few Moreton Bay Figs which are mulched to the dripline and those babies kill off grass anyway. I think the logic behind mulching to dripline is the fact that most plant books show water gathering roots extend that far. It would also be worth noting that lawns are often over fertilised with NPK and this contributes to tree nutrition problems but thats the extent of my meager knowledge.

Somebody heeeeeeelp!


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## Glennak (May 31, 2009)

So what a great way to control weeds, plant a tree, got to be better than chopping the top off the weeds every week what a waste of time.


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## asthesun (May 31, 2009)

at alot of commercial sites i do tree work, there's mulch rings, there to protect the trees from idiot lawn maintenance worker's mowers and weedwackers.


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## S Mc (May 31, 2009)

pdqdl, I see in your sign off that you state you are a certified arborist, and yet you make the statement "I have always considered trees the 'apex predator' of the plant kingdom". Viewing trees in this manner sounds counter to what an arborist is or should be.

You are evidently incredibly lucky to be in the perfect environment for tree growth. And yet for some reason you are claiming it is a curse. 

Perhaps where your logic is erring is latching onto the phrase "protecting the tree from the lawn". It is well documented that trees and turf compete. Where trees predominate the turf will suffer. Where the lawn is given all the care, the trees suffer. A golf course may have the most magnificient appearing turf imaginable. It is a contrived, artificial environment. If that is the appearance your clients want, you need to adjust your recommendations to achieve that. Unfortunately for the environment, that generally means pumping untold amounts of chemicals. (But that is a whole other post and rant.)

Picture a forest...sparse, native grasses.

Picture a prairie, sparse, scattered trees.

This would be the natural order of things. People unfortunately try to have everything, all at once, with no thought as to what is going to blend and coexist. 

The trees and grass in your area are desperately trying to tell you that they don't want to cohabitate. If your solution to no grass under a tree is to constantly try to thin the tree or raise the crown, you are in fact fighting a losing battle. We have clients that simply will not give up their grass too close to the tree, and we tell them this is a continual battle that will require maintenance. 

"Too many trees, and you won't have any lawn. Period" This sentence is true, pdqdl. But then why not go in proactively to your clients and help them select their best specimens, get rid of the "weed" trees and set up a realistic management schedule for their landscape that will minimize the use of chemicals and annoyance of running into limbs or debarking the trunks with their lawn mower? 

Trees will survive without the mulch ring. They simply will survive and thrive better with it. Your client has a dead spot, bare soil under the tree...why NOT mulch it and make it look attractive?

There is much documented evidence that roots thrive better under mulch. I am surprised as a certified arborist you have not read these reports. Google Kew Gardens. After a hurricane in the 1980s that blew over a great many trees, they discovered the roots under the grass areas were significantly less than the ones under mulch areas. Every tree that can now has a mulch ring. 

Sylvia


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## Dadatwins (May 31, 2009)

One of the functions of having a mulch ring is to make the tree site as natural as the wooded setting that trees come from. Trees growing in a natural forest have the benefit of leaves dropping and breaking down into nutrients for the tree to retake up and continue the cycle. This is how trees have survived for millennium, they create and use their own waste. Place a tree in front of a house and then add a lawn service that takes all the grass clippings away all year long, takes away all the leaves in the fall and the tree is left sitting in the same soil that it has been planted in. Without the natural benefit of the organic matter the tree will start to decline as the roots can only pull so much out of the soil. By adding a natural mulch ring, not rock or plastic, arborist are trying to duplicate the natural environment of the forest but still satisfy the aesthetics that homeowners want. In a perfect world a mulch ring to the drip-line would be ideal, but we all know that is very unlikely. As for large mature tree needing a bigger mulch ring, bigger trees needs more food.


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## TreEmergencyB (May 31, 2009)

i think the biggest advantage of mulch rings around trees is to keep them damn landscrapers from dinging them up with there mowers and weed wackers, make it out the the drip line and you will not only protect the trunk but the lower canopy also.


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## D Mc (May 31, 2009)

pdqdl said:


> ...*I have never seen a tree killed off by the lawn*, and I have never seen a mature tree mulched to the dripline, either....



How is this possible? Have you not seen young trees with their cambium irreparably damaged by routine lawn maintenance? Herbicide-sensitive trees succumb to weed and feed products? Preexisting trees decline after new lawns were set under their canopies? These are common occurances that I have seen many examples.

Trees are tough. We can all point to the magnificent tree in a grass area and say "See?" I can also point out magnificent trees growing out of rocks on a dry mountainside. But if we tried to perpetuate that environment in our landscape, we would be doomed to failure as these are the exceptions.

Dave


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## treemandan (May 31, 2009)

S Mc said:


> pdqdl, I see in your sign off that you state you are a certified arborist, and yet you make the statement "I have always considered trees the 'apex predator' of the plant kingdom". Viewing trees in this manner sounds counter to what an arborist is or should be.
> 
> You are evidently incredibly lucky to be in the perfect environment for tree growth. And yet for some reason you are claiming it is a curse.
> 
> ...



No doubt we have all seen what too much mulch can do. But they keep heaping it on. I try to sell a de-mulching but rarely get the job. Basically the de-mulching is making the ring bigger in dia and thinner in thickness, 

Kinda reminds of a show I saw on one of those landsrcaping channels. Gino's Crew. What a laugh.


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## treemandan (May 31, 2009)

TreEmergencyB said:


> i think the biggest advantage of mulch rings around trees is to keep them damn landscrapers from dinging them up with there mowers and weed wackers, make it out the the drip line and you will not only protect the trunk but the lower canopy also.



I agree.

I have to say that trying to control my weedwacker isn't the easiest thing to do. And above ground roots? Wow!


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## John Paul Sanborn (May 31, 2009)

> No doubt we have all seen what too much mulch can do. But they keep heaping it on. I try to sell a de-mulching but rarely get the job. Basically the de-mulching is making the ring bigger in dia and thinner in thickness



This is because mulch has become a commodity, so now they sell it vs the service of mulching. The more mulch they sell the better off the vendor is. The other problem is that what is sold as mulch is often a wood waste product, instead of a good healthy compost.

Recent studies of chemical uptake shows that the first 3-5 feet from the trunk does the majority of the translocation to the crown. One theory is that the rest of the system is there to maintain the support and to locate supplies for times of stress.

Yes, mulch to the dripline is hyperbole, there is not scientific evidence to back up the theory. My problem with this method is that it encourages the planting of annual gardens in the area to fill in the blank space. Perennials I like, especially if they are deep rooting prairie types that will help with water penetration....but that is another thread.



> Trees are tough. We can all point to the magnificent tree in a grass area and say "See?" I can also point out magnificent trees growing out of rocks on a dry mountainside. But if we tried to perpetuate that environment in our landscape, we would be doomed to failure as these are the exceptions.



This is the whole purpose of Arboriculture: a tree planted in a landscape has the cards stacked against it in so many ways. As stated above the removal of nutrient cycling form the urban environment is a big problem, mechanical injury, unskilled pruning and being a species introduced to a non-native environment are at the top of the list.

Taking the anecdote of the "wild" tree form a different angle can put it into perspective for the uninformed; "How many thousands of trees died in that same location as the 300 year old tree grew, or for that matter a 60 year old tree?" A tree in the wild is a numbers game, a tree in a landscape needsto be maintained to grow to it's full potential.


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## Bigus Termitius (May 31, 2009)

Hey pdqdl,

I'd support a mulch ring a few feet out anyway, maybe more, especially if there is to be a landscape, playarea, picnic table or what not.

Out to the dripline seems to me more applicable to younger trees in general. To fill in the gap on larger, more established trees, I would do a soil test, make any adjustments needed, and recommend a shade grass mix.

Years ago, my stepdad was wanting to cut down a tree for the bare earth under the canopy. I worked up the soil a bit and planted the proper variety of grass and now no more mud mess or bare earth in the front yard.

Just my 2 cents.


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## TreEmergencyB (May 31, 2009)

treemandan said:


> I agree.
> 
> I have to say that trying to control my weedwacker isn't the easiest thing to do. And above ground roots? Wow!



never mind hitting ground roots not good for the tree or your mower
:notrolls2:


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## tree md (May 31, 2009)

Just for the record, what is the best mulch to use and how deep should it be?

Also, I had to raise a bed for perennials yesterday on one of the properties I take care of. A little out of my realm but I am doing it as a favor for the Pres. of the HOA. I raised the bed using a soil developed by one of our local college horticulture departments but I had to raise the bed over the roots system of a young maple. I think the maple is like 13 years old, maybe 6-8" DBH and maybe 15' tall. I was sure not to cover the root flare or stem but I had to raise the bed about 12-14" over the root system. Any problem with that?


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## TheTreeSpyder (May 31, 2009)

The mulching is also a way to compete for space, shut out lite, retain water, stabilize temp, spread out forces to a larger foot print and provide dynamic absorption (both to not compress soil sea air space. Low branchings would also provide less light and obstacle to traffic, thereby also limiting competition, conserving water and again less compressed ground. Low branchings would also help keep light out, keep rain more to outside, and downward pointing branches help deliver water outwards (whereby upward pointing branchings tend to run water towards trunk, lowest branchings providing final routing etc. (Light thru branches is green, with red mined out of white lite, leaving light 'anemic' for plant growth, but in a band we are more sensitive to, so it seems brighter than it is.. As another form of fierce competition for life giving ground). These things are all orchestrated to the same ends. A tree out of a woods, already has odds tilted, just because it survives, does not mean it thrives.

It is not so much the air in the soil we save by less compression, but rather the air space that air, water, growth etc. can create rich, Earth, and also make it permeable. This allows a rich fauna of life, bio-diversity matters in the sea of soil! There is only so much energy, for growth etc. The 'net income' of the roots; is the riches they bring in less the expenditure to deliver etc. Less permeable ground/less airspace/more compact, is going to be less rich, and cost more energy to work for those lesser riches (double loss).

Air only penetrates so deep, and even mulch has weight, we neither want to compress, nor smother Mother Earth by too much of a good thing/mulch. Nor do we want mulch against trunk,nor on the Natural ramping of the root crown, that would serve it away from the trunk. Even though in our lysdexic ways; that is where it is first placed! No, Know; Bad ! Trunk and root crown tissue is more like above ground tissue, not root tissue, trunk and root crown must breathe etc.

We all do what we must, but it is better to have a good imagery of what is in the balance; especially when advising others. The 'new' school of tree biology is quiet simple, a tree is a living, responding thing; not just a board to dictate to as we hammer nails into it, or the tree bones we build our homes with-that we are most familiar. This is the pivotal paradigm to what we think wee know. Understanding trees can inspire a lot of respect for them!


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## M.D. Vaden (May 31, 2009)

D Mc said:


> How is this possible? Have you not seen young trees with their cambium irreparably damaged by routine lawn maintenance? ......



That would be by the person and machine. I think they meant by the grass itself.

In my work and at the homes I've lived at, even back to childhood, I can't put my finger on a tree that I can say was killed or put into ill health by having grass under it.

The most damage I've seen, was at the country clubs in low areas that were wet, were compaction from mowers and poor drainage were a problem. The drainage would have been bad even without the grass.

So I more or less agree that grass may not be much of a problem, although I do expect optimum health for many trees that are mulched because so more become premium conditions.


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## chewbacca (May 31, 2009)

tree md said:


> Just for the record, what is the best mulch to use and how deep should it be?
> 
> Also, I had to raise a bed for perennials yesterday on one of the properties I take care of. A little out of my realm but I am doing it as a favor for the Pres. of the HOA. I raised the bed using a soil developed by one of our local college horticulture departments but I had to raise the bed over the roots system of a young maple. I think the maple is like 13 years old, maybe 6-8" DBH and maybe 15' tall. I was sure not to cover the root flare or stem but I had to raise the bed about 12-14" over the root system. Any problem with that?



Yeah, I'd say 12-14" of additional soil on the root system of a tree that size is too much. Something like 90% of a trees roots are within 12-18" of the soil surface (depending on species). Those roots need oxygen, which is one reason why they're so close to the surface. By adding that much soil, you run the risk of effectively smothering those roots. I'm not saying you'll notice a decline in the tree. But, I'd be willing to say that if the tree's roots cannot grow upward closer to the surface quickly enough, it will exhaust it's "energy" reserves and, at that point, you will notice a decline in the tree. Could end up not noticing anything or it could end up bad. At any rate, it's best not to do it. Good luck.


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## D Mc (May 31, 2009)

M.D. Vaden said:


> That would be by the person and machine. I think they meant by the grass itself.



It is a moot point when you cannot have one without the other. This discussion is in regards to landscaped yards. 

You are particularly qualified to answer this: why not put a mulch ring around the tree? As a professional landscaper, would it ever be appropriate to plant non-compatible species together? 

If we, as arborists, don't get it, how can we expect the homeowner to? 

Dave


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## M.D. Vaden (Jun 1, 2009)

D Mc said:


> It is a moot point when you cannot have one without the other. This discussion is in regards to landscaped yards.
> 
> You are particularly qualified to answer this: why not put a mulch ring around the tree? As a professional landscaper, would it ever be appropriate to plant non-compatible species together?
> 
> ...



Little 3' ring - sure pretty easy.

Most of the good landscapers here can maintain turf to within a foot of the trunk without any damage. But a ring a few feet radius or circumference would not be hard.

Would really look dorky in small yards. And the reason many homeowners don't want them, is that they reduce the amount of lawn to use.

In big landscapes, the circles can look pretty nice.

Below is a before and after of one landscape renovation. I revisited after 5 years, and the homeowner maintained the grass meticulously around the maple without damaging the bark. I think a circle would look rediculous - even a small square.

Thus - he as an amateur shows he can do it right. 

If he sells the place, the next person can cut the tree ring out and mulch if they choose to.

There is about 2 weeks between these two images.


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## John Paul Sanborn (Jun 1, 2009)

tree md said:


> I raised the bed using a soil developed by one of our local college horticulture departments but I had to raise the bed over the roots system of a young maple. I think the maple is like 13 years old, maybe 6-8" DBH and maybe 15' tall. I was sure not to cover the root flare or stem but I had to raise the bed about 12-14" over the root system.



I would say "it depends" if the since the soil is probably loose enough to facilitate gas exchange, I would expect that it is not a huge problem. Since it is perennials, you are not disturbing the soil on a regular basis either.

With gardens the problem is twofold, regular tilling for the soil destroys roots, and causes a permanent state of stress. Secondly: we create the environment were encircling roots will develop; thus becoming tomorrows girdling root. These are the only times I recommend a landscape fabric; to keep tree roots from infiltration the bedding soil.




> Those roots need oxygen, which is one reason why they're so close to the surface.



A number of years a go, a college in one of The Carolinas did a tree well experiment with pines. they wanted to see the effectiveness of aeration pipes with significant grade changes. They found no difference between the test and control sites as far as health and gas exchange. Their assumption was that since they were careful to not run any equipment on the soil, so as to avoid compaction, that the compaction is the primary limiting factor in grade changes where drainage is not a factor.


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## outofmytree (Jun 1, 2009)

M.D. Vaden said:


> Little 3' ring - sure pretty easy.
> 
> Most of the good landscapers here can maintain turf to within a foot of the trunk without any damage. But a ring a few feet radius or circumference would not be hard.
> 
> ...




Nice looking job Mario.

On the other hand, if that was a runner grass planted in Australia the lawn mowing contractor would come looking for you with a blunt edger blade!

As a former "lawnie" I can tell you that tree on the verge has a life expectancy of under two years. Ring barking by brush cutter is a very common problem. Before I understood the benifit of mulch to trees I would convince my mowing clients to allow me to use the edger to create a small garden bed around the tree to avoid this. With 20/20 hindsight I was on the right track I just needed to add mulch and viola. On another note I have often wondered what a large violin has to do with an expression of accomplishment........


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## S Mc (Jun 1, 2009)

M.D. Vaden said:


> Would really look dorky in small yards. And the reason many homeowners don't want them, is that they reduce the amount of lawn to use.



And yet your illustration here shows a small yard and a great deal of mulch. All the trees between the sidewalk and the house are in mulched areas with the grass separate. A good choice with easy maintenance. However, I don't see this little boulevard amounting to usable lawn for this homeowner. It just looks high maintenance to me. 




M.D. Vaden said:


> Below is a before and after of one landscape renovation. I revisited after 5 years, and the homeowner maintained the grass meticulously around the maple without damaging the bark. I think a circle would look rediculous - even a small square.
> 
> Thus - he as an amateur shows he can do it right.
> 
> If he sells the place, the next person can cut the tree ring out and mulch if they choose to.



Most homeowners in our experience will not get down on their hands and knees and hand clip around the base of the tree, they use the weedeater. And unfortunately, the new owner will probably not go to the trouble of removing the grass and installing mulch, but will simply start the weedwacking attack.

IMHO, Mario, a design flaw in this plan. Better to have incorporated the tree within the geometric design of your squares without turf giving a better chance for long term survival of this tree.

Sylvia


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## pdqdl (Jun 1, 2009)

TreEmergencyB said:


> i think the biggest advantage of mulch rings around trees is to keep them damn landscrapers from dinging them up with there mowers and weed wackers, make it out the the drip line and you will not only protect the trunk but the lower canopy also.



I agree. Absolutely the best reason to mulch a tree. But that is no reason to mulch a 50' diameter circle under a mature tree.

That is the basis of my posting: the tendency of so many here at AS to recommend large mulch rings for every tree health issue. It's not like trees don't benefit from the large mulch rings, and the elimination of competition. It is my claim, however, that the very large rings recommended by so many are a very minor benefit in most circumstances. 

Sylvia: I don't claim to be JUST an arborist, I also claim to be a lawn expert. And I don't just have a silly certification from ISA, I have a BS in biology. When I got that degree, it included course work studying ALL the plants and animals of this world, not just the green ones that require chainsaws for maintenance.

My goal is to be as well informed as I can on as many aspects of my trade as possible, and to share that information with my customers for a fee ($). I never claimed that my only focus in this world was to protect the best interests of trees to the exclusion of the lawn, the bushes, or the rest of the biosphere, for that matter.

Yes, the lawn monkeys often kill off the trees with their string trimmers. It really pisses me off when my guys do it. But that doesn't mean that I won't thin and raise a tree because the customer wants some better grass to sit on when they are relaxing in the shade of their tree.

When was the last time you saw a photo of a romantic couple lounging in the mulch under a tree?


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## pdqdl (Jun 1, 2009)

NICE landscape Mario! 

I agree with Sylvia, though. Even I (the self declared mulch ring detractor of ArboristSite) would have given that little tree a mulch ring. It looks great, but I would expect the lawn maintenance to end up getting the bark in the end.


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## Brush Hog (Jun 1, 2009)

asthesun said:


> at alot of commercial sites i do tree work, there's mulch rings, there to protect the trees from idiot lawn maintenance worker's mowers and weedwackers.



I'm a so called idiot and proud of it . What about the lawn chemical companies spreading weed killer right next to the trees. Mulch rings would also protect them from that but those mulch volcanoes are just the opposite for a tree. A local nursery sells a mulch called forest blend. It's made up leaves,ground sticks and compost. That would be ideal around a tree I think not bright red ground up pallets.


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## pdqdl (Jun 1, 2009)

Sylvia, I think you are a dedicated arborist, and you are certainly well informed. Sometimes however, I think you miss the point.



S Mc said:


> pdqdl, I see in your sign off that you state you are a certified arborist, and yet you make the statement "I have always considered trees the 'apex predator' of the plant kingdom". Viewing trees in this manner sounds counter to what an arborist is or should be.
> 
> _Really? How does the term "arborist" suggest how we should think or "view" a certain topic? There are Certified Utility Arborists that spend their days evaluating which trees to hack out of the way of the utility lines, and there are Certified Arborists hired by their customers to argue with the Utility company. Just look at all the conflict on this site, where "arborists" are at each others throats constantly. I think many folks tune in to this site just to work out their aggressions.
> 
> ...



You should also understand that my customers would probably have a fit if I planted a young tree and didn't mulch it. I'm not averse to mulch rings, I just get tired of hearing this "add mulch" thing as a lame solution to every tree problem.


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## Bermie (Jun 1, 2009)

Whew, quite some back and forth, many valuable comments with sound reasoning to most of them!

I was going to mention Kew as well, they now mulch all the large trees if they can, out to the drip line, BUT Kew is a botanical garden and research institute, so they can afford to do it within the remit of what the place is for. I can agree that your typical HO wouldn't appreciate massive mulch rings.

It seems the overriding difference of opinion is how much grass can you get to grow under a tree and how little excessive work can you get away with doing to the tree in order for the grass to grow reasonably, and how little extra irrigation and fertilization do you have to do to the grass and not have a detrimental effect on the tree...I think.

Its the ongoing balance of a managed landscape, managing each part sufficiently without detrimentally affecting the other. 

I do work on a large estate that has two very big ficus trees that are now surrounded by a high maintenance fine putting green lawn. The lawn is sparse under the trees, ficus are naturally dense, I've thinned them twice, removed large branches, they've added irrigation, plugged and sodded under the tree. The two are incompatible, but the HO doesn't get it, both I and the estate horticulturalist know that neither the lawn or the trees will ever be their best as long as the other exists! 

The way out is compromise, plant tree species that tolerate grass under them, that have a structure and growth habit more compatible for light penetration for a lawn, allow a moderate mulch ring so the tree can get its organic matter....what you create, you must maintain...the landscapers credo (at least it was mine when I was a landscaper!)
And keep the mowers and weed whacker AWAY!!!


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## moss (Jun 1, 2009)

One aspect not covered is that mulching around the tree is theoretically an attempt to provide something like the leafy and woody detritus normally found in forest habitat. It's known that urban and suburban trees with maintained and raked lawn right up to the trunk suffer chronic starvation, the human desire for "cleanliness" and an orderly yard puts the tree at a disadvantage. All I know is I hate seeing mulch volcanoes banked up over the root flare, the mulching strategy has gone haywire in current landscaping practices.
-moss


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## Bigus Termitius (Jun 1, 2009)

pdqdl said:


> Sylvia: I don't claim to be JUST an arborist, I also claim to be a lawn expert. And I don't just have a silly certification from ISA, I have a BS in biology. When I got that degree, it included course work studying ALL the plants and animals of this world, not just the green ones that require chainsaws for maintenance.



Amen. Grasses and other plants have rights too!


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## tree md (Jun 1, 2009)

Man, I can't tell you how many requests I get to remove trees so they can get grass growing in the yard every year but it's a bunch. The Sweet gum seems to be one of the most despised.


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## M.D. Vaden (Jun 1, 2009)

S Mc said:


> IMHO, Mario, a design flaw in this plan. Better to have incorporated the tree within the geometric design of your squares without turf giving a better chance for long term survival of this tree.
> 
> Sylvia



Many neighborhoods are *requiring* sod in the strip.

Tree pre-existing.

Now here is something to consider for around trees - FAKE GRASS. For those who won't get on their hands and knees as you suggested. This back yard has no trees at all in the lawn. Other than pruning a few small trees in the pots and beds, I took this one just to show people what the artificial lawns look like. 

Maybe this is what they should put in *planter strips* by the street around trees.

One bad thing fake grass may cause though, is it will get old at some point, and unless it can be recycled, will stuff landfills faster.


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## treemandan (Jun 1, 2009)

M.D. Vaden said:


> Many neighborhoods are *requiring* sod in the strip.
> 
> Tree pre-existing.
> 
> ...



So where is the fake grass?


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## M.D. Vaden (Jun 1, 2009)

treemandan said:


> So where is the fake grass?



You are being funny right 

You're looking at it.


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## S Mc (Jun 1, 2009)

pdqdl said:


> I agree. Absolutely the best reason to mulch a tree. But that is no reason to mulch a 50' diameter circle under a mature tree.
> 
> That is the basis of my posting: the tendency of so many here at AS to recommend large mulch rings for every tree health issue. It's not like trees don't benefit from the large mulch rings, and the elimination of competition. It is my claim, however, that the very large rings recommended by so many *are a very minor benefit in most circumstances*.



You know, Pdqdl, we have asked several plant pathologists (you know those braineacs with the big degrees? as in PhDs) what would be the best thing you could do for a tree...the single, best thing to be done? The response: mulch rings. We ask every time we run into one of these people. You know what they don't say? Plant a lawn and then pour chemicals and fertilizers. 



pdqdl said:


> Sylvia: I don't claim to be JUST an arborist, I also claim to be a lawn expert. And I don't just have a silly certification from ISA, I have a BS in biology. When I got that degree, it included course work studying ALL the plants and animals of this world, not just the green ones that require chainsaws for maintenance.



Whereas David would argue this point, I don't have a BS in anything. I don't claim to be an expert in anything. I have an abiding passion and love for our environment, for all living things and feel that our world is on the brink of disaster. Beyond that, I love trees. I love seeing well maintained and sustainable landscapes. It breaks my heart to see trees, shrubs, and flowers and, yes, turf, planted with little thought to long-term survival. 

We have been sold a bill of goods from the chemical companies that we belong in a weed free, high-maintenance turfed environment.



pdqdl said:


> My goal is to be as well informed as I can on as many aspects of my trade as possible, and to share that information with my customers for a fee ($). I never claimed that my only focus in this world was to protect the best interests of trees to the exclusion of the lawn, the bushes, or the rest of the biosphere, for that matter.
> 
> Yes, the lawn monkeys often kill off the trees with their string trimmers. It really pisses me off when my guys do it. But that doesn't mean that I won't thin and raise a tree because the customer wants some better grass to sit on when they are relaxing in the shade of their tree.



With your background and education I feel you have the inate ability to assist your clients in making it all work. You shouldn't view it as looking at one aspect, excluding all others. Working towards the best situation will make everything better. 

What that solution is, as you should well know, will vary with every yard you walk into. Going in with only one plan will make most of them wrong. But with your studying ALL plants and animals of this world, you should already know that. 

And I have to say, I would not retain employees who weedwacked client's trees. That would be prevented from the outset. If the trees were in lawn areas that the client was unwilling to have changed by even the smallest guard device or preventative ring, then those trees would be hand clipped, with the notation to the client that this required extra time and charge. If your employees damage personal property are they allowed to keep doing it? Why would you keep letting them damage the trees? If you had an employee who couldn't figure out the complexity of a high skill mower, would you let him or her keep operating it?

Sylvia


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## M.D. Vaden (Jun 1, 2009)

S Mc said:


> You know, Pdqdl, we have asked several plant pathologists (you know those braineacs with the big degrees? as in PhDs) what would be the best thing you could do for a tree...the single, best thing to be done? The response: mulch rings. We ask every time we run into one of these people. You know what they don't say? Plant a lawn and then pour chemicals and fertilizers.



There is another way to look at this too.

One can approach the urban landscape as separating the best thing for the tree, from the best thing for the lawn. What some people don't know how to do, is provide the best for the TREE+LAWN combination.

It's handy to be able to provide solutions for trees alone, lawns alone, and trees plus lawns together.

*If someone calls me and asks what's the best for a tree, answer is, I need to see that tree.*

If a tree was removed on the west next door, the best thing is a shrub planted to shade the bark, or a screen during that summer. If the neighbors poured a RV pad next door slightly uphill, the best thing for that tree is a drain line or grade change to handle the water.

Handled that way, the best thing for the tree is at times antithesis to the sole solution of mulch-rings.


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## pdqdl (Jun 2, 2009)

S Mc said:


> [parts deleted for brevity]
> 
> We have been sold a bill of goods from the chemical companies that we belong in a weed free, high-maintenance turfed environment. ....
> 
> Sylvia



The chemical companies have very little to do with it. They are only responding to a market that actively seeks better pesticides and fertilizers. Now if you mean the companies marketing the Lawn applications and their products...that's another story.

I have discovered that there is a large part of the population that fears "chemicals". Chemicals are BAD, and DANGEROUS, and they are NO GOOD for the environment.

In many cases, this is true. Particularly when they involve illegal dumping.

More often, people fear what they do not understand, and they do not fear what they are familiar with, regardless of the danger.

In support of this argument, allow me to submit: we all drive to work in vehicles powered by massively exothermic chemical reactions. Not many complain about the chemical hazard, but we have learned about the pollution and carbon problems associated with it. Many people won't get on an airplane, but they will not question getting in the car and racing down to the train station, a much more dangerous activity.

_MOST_ of us wash our bodies, clothes and homes with a panoply of exotic chemicals, yet because we are accustomed to them from birth, no one seems to get too excited about the regular applications of toxic chemicals we dump on ourselves. Ever see what a single drop of shampoo does to an aquarium full of tropical fish? All that stuff goes to the sea, too. 

Ever read a food label? TRY to find one that doesn't list several ingredients that you can't grow in your backyard.

Here's a good one for you: we surround ourselves with products that are the product of an entire branch of science called "Organic Chemistry", yet the number one marketing phrase that denounces the advances of chemistry is to call something "organic". All your plastics, all your pharmaceutical products, all the paints, and yes, all the pesticides and herbicides are the product of "Organic" chemistry.

In a thread not too long ago, herbicides to control noxious plants were being discussed, and any number of AS members volunteered that it was quite Ok to use salt, diesel fuel, or other "common" poisons. In fact, the damage caused by those product would be worse than by the product labeled for that application; unfortunately, they were quite comfortable with using *SODIUM CHLORODE * or *Long chain aliphatic hydrocarbons* to kill off those objectionable plants. This is just another case of people fearing the unfamiliar, and NOT fearing what we have become accustomed to.

Oops. Sorry Sylvia, I know that was almost an entirely different topic that I took off on, but I felt entitled, since you diverged into firing all lawn workers if they ever knocked the bark off a tree. And if you really think you can take one of the most illiterate, unskilled trades in the world and make them into efficient representatives of their employers best wishes for the customer...well you are much better at managing people than I am.


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## S Mc (Jun 2, 2009)

pdqdl said:


> Oops. Sorry Sylvia, I know that was almost an entirely different topic that I took off on, but I felt entitled, since you diverged into firing all lawn workers if they ever knocked the bark off a tree. And if you really think you can take one of the most illiterate, unskilled trades in the world and make them into efficient representatives of their employers best wishes for the customer...well you are much better at managing people than I am.



No need to apologize, pdqdl. Any time you want to slam chemical usage, I am right there with you. However, I'm not convinced that was your intent, but perhaps I am wrong.

If any worker refused to obey specific and detailed protocol of on site performance after sufficient training, I would indeed consider this grounds for termination of employment. This recourse would be taken only after discussion to be sure no misunderstanding existed that could not be rectified. 

We often work at an arboretum where the volunteer assistants were allowed to weedeat around the trees. Once we came on board, we made it clear this was a policy that could not continue. It stopped immediately. I don't see the problem here. 

But the general tone of your thread here, is why use "silly" mulch rings. As I have said, promoting the best environment for whatever species you are trying to grow, simply makes sense. You wouldn't plant a full shade plant out in the full sun and expect it to do well. If we plant KBG here in full shade, it will not thrive. In my Turf Management class the recommendations for best management of turf, stated over and over again, was proper selection of species for your particular site, cultural practices that enhanced the performance of that particular species to allow for least use of chemicals and fertilizers which would make for a stronger turf; one that would be able to assist in its own survival at the expense of weeds and competition.

If a client has a postage stamp yard, with a large shade tree, you aren't going to recommend a full sized mulch ring. If a client has a larger site, separation of turf and trees is a well-thought landscape design. This principle was emphasized over and over again in the Landscape Design classes I have taken. 

"Lawn should not be used on the ground plane in *shaded areas below tree canopies, *on slopes over a 3:1 gradient, in small pieces here and there, or in long narrow spaces, such as along the side of the house near the property line. Lawn is difficult to grow and maintain in these instances." Residential Landscape Architecutre, Design Process for the Private Residence, Booth and Hiss. (Bold emphasis mine.)

Because these biologically sound and common sense design solutions are not adhered to more, gross amounts of chemicals are poured into the environment needlessly. "About 40 percent of all private lawns are treated with pesticides at a rate that is three to six times more per acre than that used by farmers." ibid

So, I personally find these sound principles worthy of consideration and try to impart this information to our clients just as we do when discussing proper pruning techniques. This all comes under the heading of PHC and BMPs.

Sylvia


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## BC WetCoast (Jun 3, 2009)

Just to sidetrack the discussion slightly, I find it interesting that fruit orchards in the Okanagon valley plant grass under the fruit trees. I understand that the objectives of fruit trees are different than ornementals, but it would be logical that the orchardists should put mulch under their trees. Less maintenance and better for the trees? 

Given all the research that goes into fruit tree production, why isn't this done? Or is it done and I'm just not aware of it.


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## M.D. Vaden (Jun 3, 2009)

BC WetCoast said:


> Just to sidetrack the discussion slightly, I find it interesting that fruit orchards in the Okanagon valley plant grass under the fruit trees. I understand that the objectives of fruit trees are different than ornementals, but it would be logical that the orchardists should put mulch under their trees. Less maintenance and better for the trees?
> 
> Given all the research that goes into fruit tree production, why isn't this done? Or is it done and I'm just not aware of it.



My guess would be that the mulch is detrimental to maintenance.

Mulch grows weeds, and I can't imagine trying to hand-weed an orchard, unless someone wants to increase herbicide use.

With grass, it's pretty easy to just mow the grass, and weeds would not matter.

I suppose they could mow weeds in the mulch, but having run mowers over mulch before, it's rather messy when chips go flying in every direction.

That's a guess.


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## yibida (Jun 3, 2009)

*Natures been showing us the benifits for years.*



S Mc said:


> pdqdl, I see in your sign off that you state you are a certified arborist, and yet you make the statement "I have always considered trees the 'apex predator' of the plant kingdom". Viewing trees in this manner sounds counter to what an arborist is or should be.
> 
> You are evidently incredibly lucky to be in the perfect environment for tree growth. And yet for some reason you are claiming it is a curse.
> 
> ...



:agree2:
Years of a natural mulch layer being produced in forests has always shown a multitude of benefits. Nutrient availability, suppression of weed growth, moisture retention, and so on.

To continually mulch around trees especially at juvenile stages has great benefits with aiding establishment but by creating a false economy of over fertilizing and watering because of lawn areas will always have an adverse effect long term if restriction on water use or not maintaining a regime of fertilizing occurs.


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## John Paul Sanborn (Jun 3, 2009)

My post of a few days ago got lost in the aether, so here are a bunch of thoughts more disjointed then usual.



yibida said:


> To continually mulch around trees especially at juvenile stages has great benefits with aiding establishment



I would add the caveat that annual mulch additions, especially of the commercial twice ground, can interlock to the point of becoming hydrophobic. I've seen mound plantings that are bone dry under the mulch, even though there is a torrential downpour flooding the yard.

From an intuitive level, I like the idea of mulch sandwiching: every time mulch is renewed a layer of true compost is added first.

I think it was Russ Carlson, he did a survey of his yard and found the macrobiota count eightfold higher in soil under the mulch vs a few feet away in the turf.

The biggest problem with mulch is that it has become a commodity that is redefined ground wood-waste. There seems to nolonger be a requisite composted component to it. A landscraper puts down a colored ground construction waste product and it is mulch. 

We all agree that mulch volcanos are bad.


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## pdqdl (Jun 3, 2009)

I think some of you folks have misunderstood my intent. That, or my original post has been forgotten. I am not opposed to tree mulch rings. I put them around every tree I plant. I like the appearance of a properly placed mulch ring, and it's a great spot to add landscaping features as well. Let me re-state my complaint, with highlights:



pdqdl said:


> Every time someone mentions lawn and trees in the same breath (here at ArboristSite), someone always seems to pipe in with the comment to *add* mulch out to the dripline.
> 
> ... and I have never seen a *mature *tree mulched to the dripline, either.
> 
> ...WHY do you folks keep telling us to increase the mulch ring to protect the tree from the lawn?



I certainly understand the value of placing plant species where they are well suited. My worst enemy is not the homeowners, nor the negligent lawn workers that damage the plants, it is the landscape architects that keep designing landscapes with stupid plants that look exotic when planted and then die off by the time the warranty is over.

My point is real simple: I don't see any benefit to the HUGE mulch rings so often recommended by some here at ArboristSite. I can show you many threads where someone mentions a tree problem, and the most often recommended solution is to "mulch to the dripline".

I still have not heard a compelling argument for this practice, although I certainly will concede that a native woodland setting is self-mulching by default, as the grass has died off beneath the trees.


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## D Mc (Jun 3, 2009)

pdqdl said:


> My point is real simple: I don't see any benefit to the HUGE mulch rings so often recommended by some here at ArboristSite.






John Paul Sanborn said:


> I think it was Russ Carlson, he did a survey of his yard and found the macrobiota count eightfold higher in soil under the mulch vs a few feet away in the turf.




Dave


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## lh3 (Jun 3, 2009)

*Questions*

So, how do you know the store-bought mulch is doing anything? And, where does most store-bought mulch come from? Does it have anything bad in it? Is most tested or certified to be free of bad stuff? What about the dyes used in a lot of mulch? How does store bought mulch compare to natural "forest floor" mulch? Do the good things out-weigh the bad or the other way around?


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## Bigus Termitius (Jun 3, 2009)

I've got the ulimate solution....fake grass and fake trees. Problem solved.

Don't forget the fake mulch..fake rocks..fake fireplace..fake...fake...fake...flake!


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## pdqdl (Jun 3, 2009)

John Paul Sanborn said:


> ...
> 
> I think it was Russ Carlson, he did a survey of his yard and found the macrobiota count eightfold higher in soil under the mulch vs a few feet away in the turf.





S Mc said:


> ...There is much documented evidence that roots thrive better under mulch. I am surprised as a certified arborist you have not read these reports. Google Kew Gardens. After a hurricane in the 1980s that blew over a great many trees, they discovered the roots under the grass areas were significantly less than the ones under mulch areas. Every tree that can now has a mulch ring.
> 
> Sylvia





pdqdl said:


> I promise to listen carefully, but only to compelling, thoughtful, and well documented arguments.



I will look up, understand, and evaluate any reference that is included in this thread. So far, all that has occurred is that I have been advised to find information for myself. From my perspective, all that means is that you have your opinion, and you cannot or don't wish to forward the documentation.

The whole purpose of my thread was to challenge the "huge mulch ring" enthusiasts to document their claims, not to just get into a pointless debate where each party flings invective and adverse opinions at each other.

Really folks, I'm not just being an agitator, although I will admit to being annoyed by blind allegiance to a concept. Well informed allegiance is something I respect...So convince me!


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## Ed Roland (Jun 3, 2009)

pdqdl said:


> WHY do you folks keep telling us to increase the mulch ring to protect the tree from the lawn?



Not from the lawn, from the lawn "technician"!

Lesco hort supply suggests you fertilize your centipede lawn 6 times a year. Scott's says, what, 5 or so? 

pdqdl, obviously you recognize the benefit of grass that needs mow and blow as often as po$$ible but are you aware of the ill effects of forcing woody perennials to grow at this manufactured rate? A 50' diameter mulch ring will help protect the tree from whatever junk science is being performed on the lawn.

Great thread, by the way.


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## D Mc (Jun 3, 2009)

pdqdl said:


> I don't claim to be JUST an arborist, I also claim to be a lawn expert. And I don't just have a silly certification from ISA, *I have a BS in biology. * When I got that degree, it included course work studying ALL the plants and animals of this world, not just the green ones that require chainsaws for maintenance.



Really, were you awake? If you indeed have a BS in biology, obviously not soil biology, but learned about all the other plants and animals of the world, you already know the answer. 

I'm posting a link that took me 30 seconds to find on a google search. 

http://www.mortonarb.org/images/stories/pdf/our_work/Tree_vs_Lawn.pdf

The information on the benefits trees derive from mulch abounds. But you will not see this unless you open up you mind.

Dave


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## M.D. Vaden (Jun 3, 2009)

D Mc said:


> Really, were you awake? If you indeed have a BS in biology, obviously not soil biology, but learned about all the other plants and animals of the world, you already know the answer.
> 
> I'm posting a link that took me 30 seconds to find on a google search.



I noticed what seems to be a deficiency in that paper ... 

Anyhow, plants in close proximity do not always compete. And if needed, it is available to supply the moisture and nutirent needs of several plants in close proximity. The paper did mention plants of similar needs in proximity, but was not limited to that.

In many situations, competition is minor or inconsequiential. This photo is an ancient example that crushes that paper's opening statements. The ferns beneath are doing just fine. That's why I think each tree and it's habitat must be treated on an individual basis.

I've worked at several country clubs, and noticed that trees often dominate a spot, with turf dying beneath completely. Hence, the paragraph about turf dominating reads as a misrepresentation. At least we can extract the best ideas from articles like that, filtering the content with other knowledge and experiences.

One more thing - the stunting mentioned in the .pdf. As long as trees can have good longevity, there are people that would prefer a bit of stunted growth. Bonsai being one of the most notable examples. Bonsai even requires slight starvation sometimes, or diminished nutrition.

So all-in-all, the .pdf article once again approaches education with a one size fits all point of view, rather than offering a multitude of solutions that people can utilize.


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## John Paul Sanborn (Jun 3, 2009)

> Really folks, I'm not just being an agitator, although I will admit to being annoyed by blind allegiance to a concept.



I'm sorta agreeing with you, partially: mulching to the dripline is overkill.

So I should document research, but you don't have to? 

refute my opinions please;

Turf an artificially maintained environment that is close to a monoculture. Maybe three genus of grass grown with a mix of species. 

Turf management removes the nutrient cycle from the urban/exurban environment; if we mulch the grass, it still does not have much nutrient value to it. Most people do not want the annual leaf fall to be mulched in. Not only doe this starve the environment of minor and trace minerals and elements, it makes for an organic poor topsoil. How many people have their lawns top-dressed on a regular basis?

Low organic soils lack a diversity of beneficial macro and micro-biota.

We could go on...


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## Ed Roland (Jun 3, 2009)

pdqdl said:


> When was the last time you saw a photo of a romantic couple lounging in the mulch under a tree?



Do you volunteer the information concerning the residual of a chemical with a class 3 Acute Hazard Warning rating (_Dimension_ with turf fert) as they lounge and frolick in this luscious weed free grass?

Turf care can be at odds with tree care, plain and simple. This is an excellent thread to illustrate these conflicts. Why not try to separate your efforts to induce turf growth with our efforts to maintain long term tree care with a nice fat line of delineation such as mulch all the way to the drip or even WELL beyond? As you know the tree feeder roots do mostly inhabit the same space within the soil as your multitude of grass plants. 

Let mulch deliver the elements to fuel tree processes instead of allowing the Scott's corp to dictate the growth that equals bottom line billing.


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## outofmytree (Jun 4, 2009)

Hey pdqdl Im on your side mate!!! 

Thought you might appreciate some support rather than the barrage you have received from the flock of the faithful thus far.

I am not in the lawn care business any more. I was. No longer. However I can tell you as an urban arborist that for every client that says kill the grass I love my tree there have been 20 who say, cut that damn tree down its leaves are ruining my lawn. This is reality. Not some mythical land where the tree fairy sits on the arborists shoulder and Mr/s Public take advice. In the real world you must be able to balance the needs of the client with the needs of the tree and mulching to the dripline in most situations isnt going to happen. 

As to the size of mulch rings that will provide real benifit perhaps someone with more botanical knowledge could supply a link or reputable fact to determine where at least 75% of the trees roots are located. That distance from the trunk would give a realistic size to a mulch ring as a blueprint then it can be adjusted according to species, soil type, and location.


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## tree md (Jun 4, 2009)

Been a long time since I was in landscaping and turf management (even went to school for that many moons ago) but we used to try to design natural areas for the trees with an island for mulch and usually pine strawed over it (in GA). We would try to create a nice large natural island for areas where there was a small grove of trees and rings around solitary trees in the turf areas. Trees in the large islands always seemed to do better than the solitary trees (especially the young ones) where we would typically only mulch maybe out to three feet. An added benefit (IMO) was there was less turf to manage and healthier trees overall. I also think the natural areas are more aesthetic looking and creates diversity.


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## Bigus Termitius (Jun 4, 2009)

I'm surprised no one has mentioned Allelopathy yet. It seems to me that it must be a consideration in some cases.


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## Bigus Termitius (Jun 4, 2009)

M.D. Vaden said:


> I noticed what seems to be a deficiency in that paper ...
> 
> Anyhow, plants in close proximity do not always compete. And if needed, it is available to supply the moisture and nutirent needs of several plants in close proximity. The paper did mention plants of similar needs in proximity, but was not limited to that.
> 
> ...



Good post.


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## Ekka (Jun 4, 2009)

M.D. Vaden said:


> I noticed what seems to be a deficiency in that paper ...
> 
> Anyhow, plants in close proximity do not always compete. And if needed, it is available to supply the moisture and nutirent needs of several plants in close proximity. The paper did mention plants of similar needs in proximity, but was not limited to that.
> 
> In many situations, competition is minor or inconsequential.



I noticed what seems to be a deficiency in your reasoning. :monkey:

Do have any data, photographic and validated evidence to support your claims? Or is it another generalization?

In the picture you posted the undergrowth was ferns, I wonder what the redwood's root density comparison would be if we took a soil core and compared it to a location where there was no ferns and just mulch (on the indigenous forest floor that is). 

What you are suggesting here is that an almost symbiotic relationship exists between species occupying the same soil area. If that's the case then it needs to be scientifically validated and added to this list perhaps (or one like it).

http://en.wikipedia.org/wiki/List_of_symbiotic_relationships


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## yibida (Jun 4, 2009)

*What Iv'e found using chipper mulch.*

As someone mentioned earlier, good thread. opcorn:

I wonder if anyone has performed documented trials on mulching and not mulching trees in a controlled environment during establishment.

Hydrophobic layers of mulch developing are a concern if mulch layers are non permeable to start with (very fine mulch seems to develop this problem). Coarse mulch doesn't seem to do the job as well though as weed growth takes a stand readily.

If mulch is applied in a green state and not composted correctly fungal growth develops and adds to a hydrophobic development within layers and the mulch becomes biscuit like over time.

I have also read somewhere (sorry not sure of reference) that nitrogen draw down during composting robs the tree / shrub / plant as opposed to sustaining and fixing nitrogen when fresh mulch is used over long periods.

That said a mixture of a broad spectrum of components that are composted, ie.. leaves, twigs, wood, bark, fruit, etc.. in mulch seems to work better for me rather than an aesthetic one containing one ingredient.


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## Ekka (Jun 4, 2009)

yibida said:


> As someone mentioned earlier, good thread. opcorn:
> 
> I wonder if anyone has performed documented trials on mulching and not mulching trees in a controlled environment during establishment.
> 
> ...



http://www.sgaonline.org.au/info_mulch_chunky_or_fine.html


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## Bigus Termitius (Jun 4, 2009)

Yes, but don't we find plants and trees growing in apparent harmony in nature?

Not necessarily symbiotic, though possible, but they seem to be able to at the very least coexist, and perhaps optimization isn't always the intent per the original design.

However, I can see where, at times, optimization is desired and even needful.

I liked M.D. Vaden's post for the balanced approach and the understanding of different situations along with the considerations for an array of variants.

I don't think the whole truth resides in either camp.


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## yibida (Jun 4, 2009)

Ekka said:


> http://www.sgaonline.org.au/info_mulch_chunky_or_fine.html




Thanks Ekka, makes sense to me just gotta trade in the back yard 4inch chipper for a bigger one.

With the drought Ive a mind to use it though as opposed to prayin for rain.


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## D Mc (Jun 4, 2009)

outofmytree said:


> As to the size of mulch rings that will provide real benifit perhaps someone with more botanical knowledge could supply a link or reputable fact to determine where at least 75% of the trees roots are located. That distance from the trunk would give a realistic size to a mulch ring as a blueprint then it can be adjusted according to species, soil type, and location.





http://edis.ifas.ufl.edu/WO017

During tree root growth trials in Florida and New Jersey, excavation of root systems revealed that tree roots grew beyond the branch drip line for all six species tested, but the lateral extent was species dependent. Green ash roots, for instance, grew from the trunk 1.7 times further than the branch spread. Southern magnolia, on the other hand, had roots out to 3.8 times the dripline. On average, tree roots spread close to 3 times the spread of the branches, so that a tree with an 8-foot branch crown spread would have a 24-foot root spread diameter


Dave


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## S Mc (Jun 4, 2009)

tree md said:


> Been a long time since I was in landscaping and turf management (even went to school for that many moons ago) but we used to try to design natural areas for the trees with an island for mulch and usually pine strawed over it (in GA). We would try to create a nice large natural island for areas where there was a small grove of trees and rings around solitary trees in the turf areas. Trees in the large islands always seemed to do better than the solitary trees (especially the young ones) where we would typically only mulch maybe out to three feet. An added benefit (IMO) was there was less turf to manage and healthier trees overall. I also think the natural areas are more aesthetic looking and creates diversity.



Well said and good observations. The proof is in front of us...we just have to open our eyes to recognize it.

Sylvia


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## S Mc (Jun 4, 2009)

Ekka said:


> I noticed what seems to be a deficiency in your reasoning. :monkey:
> 
> Do have any data, photographic and validated evidence to support your claims? Or is it another generalization?
> 
> ...





Gad, Ekka, you took my post away. I was going to say virtually the same thing.

A photo of redwoods and nitrogen-fixing ferns...the ultimate companion planting...check the mulch under *those* trees.

This thread is specific to turf and grass and the relative size of mulch rings. IMHO a small mulch ring, where it is better than nothing, is a mere physical protection for the trunk against lawn mowers and weedeaters. The small absorbing roots are out further (depending on the size and species of the tree). They grow, die and regrow along the main root and tip of that root. Again depending on the size and species of the tree, these absorbing roots can go out 2 to 3 times the canopy of the tree. Well, beyond the dripline. 

This is why I so often say, "out to the dripline if possible". Because I realize it is not always possible, I am trying to recommend protection of as much of the nutrient-uptaking roots as I can.

Sylvia


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## pdqdl (Jun 4, 2009)

woodweasel said:


> Not from the lawn, from the lawn "technician"!
> 
> Lesco hort supply suggests you fertilize your centipede lawn 6 times a year. Scott's says, what, 5 or so?
> 
> ...



Well, I won't deny that claim at all. But that is not what all the giant mulch ring proponents are claiming. They usually claim that they are eliminating competition from the turfgrass roots.


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## lh3 (Jun 4, 2009)

Are my questions invalid to the topic? I am not an a professional arborist, but would still like to learn a little more about what is supposed to be helping my trees physically or chemically.


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## pdqdl (Jun 4, 2009)

D Mc said:


> Really, were you awake? If you indeed have a BS in biology, obviously not soil biology, but learned about all the other plants and animals of the world, you already know the answer.
> 
> I'm posting a link that took me 30 seconds to find on a google search.
> 
> ...



That was a nice, well written article in support of your claims. I am sure that there is a great deal of merit to the facts that it presents. But it doesn't meet my standard of evidence. I expect something more scholarly that shows actual research, methodology, and purports to have a more objective viewpoint. The article you cited is just that: just an article. It's not what I would call documentation.


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## outofmytree (Jun 4, 2009)

D Mc said:


> http://edis.ifas.ufl.edu/WO017
> 
> During tree root growth trials in Florida and New Jersey, excavation of root systems revealed that tree roots grew beyond the branch drip line for all six species tested, but the lateral extent was species dependent. Green ash roots, for instance, grew from the trunk 1.7 times further than the branch spread. Southern magnolia, on the other hand, had roots out to 3.8 times the dripline. On average, tree roots spread close to 3 times the spread of the branches, so that a tree with an 8-foot branch crown spread would have a 24-foot root spread diameter
> 
> ...




Thanks for the link Dave. Gonna have to read more of this as I always thought the drip line was the approximate extent of the root system of most trees. Doh!


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## pdqdl (Jun 4, 2009)

John Paul Sanborn said:


> I'm sorta agreeing with you, partially: mulching to the dripline is overkill.
> 
> So I should document research, but you don't have to?
> 
> ...



Thanks for the support. You may not be aware of some of the more current trends in lawn maintenance. 

Since the advent of laws preventing yard waste in landfills, lawns are rarely bagged anymore, although it certainly occurs. All but one of my customers have been converted to mulching.

Leaf accumulations are now being handled (only by a few, more astute lawn service operators) by mulch mowing the leaves in place. You blow all the leaves out from under the bushes (already mulched areas!) and then circle cut the lawn until the leaves are in a pile in the center. Then mow over it until they turn to dust. Take your blower and spread the remnants over the lawn. This has several advantages: it cuts WAY down on the labor to remove the leaves, it eliminates the need for disposal, and it returns the organic material to the earth from which it came.

Follow that with lawn aeration, and you have genuine topsoil re-generation, better and much faster than nature can provide. Heavy clay soils become modified in the top 3"-6" with organic materials and the lawn is dramatically improved, as well as having lowered watering requirements.

So a lawn service can actually return more of their yard waste to the soil than a tree service can. I don't know of too many situations where the tree gets chipped in place and left on the ground it came from. My business does that pretty often, but only in rough terrain situations where the quality of appearance is not important. Even then, we do it as a means to reduce expense or provide erosion control for the bare ground.


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## pdqdl (Jun 4, 2009)

Ekka said:


> http://www.sgaonline.org.au/info_mulch_chunky_or_fine.html



Good article Ekka! 

Who would have thought that fine mulch sucked water from the soil? I still question the evaporation rate of the fine mulch. I wonder what controls they had for long term evaporation rate?

I would prefer to see moisture content readings (and temperature recordings as well) at various depths under bare ground and the different types of mulch. In my opinion, that would be a better way of comparing the relative value of the moisture retention qualities of different types of mulch.


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## pdqdl (Jun 4, 2009)

woodweasel said:


> Do you volunteer the information concerning the residual of a chemical with a class 3 Acute Hazard Warning rating (_Dimension_ with turf fert) as they lounge and frolick in this luscious weed free grass?
> ...



Huh? Here is the label (below) for Dimension (without fertilizer). Precautionary statements are standard issue, pretty much the same as everything else. 


No mention of a "class 3 Acute Hazard Warning". I suspect that warning comes from someone other than the government. I never heard of ANY "classes" of warnings concerning chemical usage. It is not part of the terminology endorsed by the EPA for certified applicators.

Missouri law REQUIRES that every application include the specific EPA registration numbers of every product used, whether done to lawn or trees. So technically, yes! Every customer knows what is put on their lawn. 

On a more practical basis, they are completely ignorant, and seldom check anything out for themselves. If they were motivated in that direction, they would probably be doing the work themselves.


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## ddhlakebound (Jun 4, 2009)

pdqdl said:


> TBut it doesn't meet my standard of evidence.
> 
> It's not what I would call documentation.



Wouldn't it be easier just to say "I choose to disbelieve reality and substitute my own."?

The control conditions you seem to require for scientific testing are pretty difficult to attain over a large sample through time in nature. Just too many variables to account for. That DOES NOT mean that the evidence we have available is discardable. 

It's simple, and it's been proven. 

Proper organic mulching provides multitudes of benefits to trees over allowing them to compete with turf. The larger the area of mulch, the greater the benefit. 

We all know that very few homeowners will follow the advice to mulch all the way out to the dripline, but if they know that's the target area, they are more likely to mulch a small to moderate area, which will still provide the tree some benefits. 

The evidence I'd like to see is regarding windthrows and mulching. How many trees could have remained standing if they'd had just a bit more mass to their root system, which mulching would have helped provide?


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## pdqdl (Jun 4, 2009)

D Mc said:


> http://edis.ifas.ufl.edu/WO017
> 
> During tree root growth trials in Florida and New Jersey, excavation of root systems revealed that tree roots grew beyond the branch drip line for all six species tested, but the lateral extent was species dependent. Green ash roots, for instance, grew from the trunk 1.7 times further than the branch spread. Southern magnolia, on the other hand, had roots out to 3.8 times the dripline. On average, tree roots spread close to 3 times the spread of the branches, so that a tree with an 8-foot branch crown spread would have a 24-foot root spread diameter
> 
> ...



I'm not sure how this legitimate documentation supports the cause of giant mulch rings. I have known for many years that tree roots extend far beyond the dripline. Haven't we all read how Dutch Elm disease was spread from tree to tree by interconnecting roots, far away from each other?

Even if you take figures from the smallest diameter root zone quoted (1.7), the surface area of the root zone under the entire dripline is only 35% of the entire root zone . At 3.8 times the dripline, your giant mulch ring is covering only 7% of the root zone!

Are you telling me that those poor magnolia trees are loosing the battle for water and nutrients with the turfgrass, and you are only going to give them a 7% leg up on the competition? Are these the same poor trees that got blown over in the hurricane study cited previously?

So why do you suppose these trees have this giant root zone? It is because they CAN. It is because the lawn has very little to say about where the tree sticks it's roots. The trees put out as many roots as they can because they have a giant need for water, less so for nutrients. 

Almost nothing can stop tree roots, if you give them enough time. We all know how they displace sidewalks, curbs, and streets. In southern Missouri, there is a cave with tree roots coming into the roof of the cavern 160' underground! 

Please don't take these arguments as a claim that trees are indestructible. The trees have developed this impressive rooting capability because it is so important to their existence. It is why protection of the root zone is so important. From people, from chemicals, from soil compaction, perhaps...but not from the grass. Just look rationally at your own evidence.

So for, no one has shown me how turfgrass is killing off the trees. Your own evidence shows that a mulch ring to the dripline actually provides very little protection (on a area-related mathematical basis) from that killer turfgrass. Damn that bluegrass and fescue, always choking those poor trees to death!


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## Ed Roland (Jun 4, 2009)

pdqdl said:


> Huh? Here is the label (below) for Dimension (without fertilizer). Precautionary statements are standard issue, pretty much the same as everything else.
> 
> 
> No mention of a "class 3 Acute Hazard Warning". I suspect that warning comes from someone other than the government. I never heard of ANY "classes" of warnings concerning chemical usage. It is not part of the terminology endorsed by the EPA for certified applicators.
> ...



The *Acute Hazard Warning Label *on Formulated pesticide products (which usually include inert ingredients) are required to carry an acute toxicity rating by the *U.S. EPA* which is reflected in the warning label on the pesticide container. The U.S. EPA gives a warning label of Category 1 to the most acutely toxic pesticide products and Category 4 to the least acutely toxic pesticide products.

PAN Pesticides Database @ http://www.pesticideinfo.org/Detail_Product.jsp?REG_NR=06271900487&DIST_NR=062719

*Product Name: Dimension turf herbicide

Acute Hazard Warning Label > 2 Warning*

Citation: Kegley, S.E., Hill, B.R., Orme S., Choi A.H., PAN Pesticide Database, Pesticide Action Network, North America (San Francisco, CA, 2009), http:www.pesticideinfo.org.
© 2000-2009 Pesticide Action Network, North America. All rights reserved.

So, actually dimension turf fungicide carries a "warning" instead of "caution" acute toxicity rating. This indicates its pretty nasty stuff. The point is that i would rather lounge in the tree mulch than on your perfect lawn. 

Herbicides, fungicides, insecticides and 5 fertilizations a year to maintain the grass monoculture. The tree roots unfortunately are intertwined throughout the same space within the soil as the grass roots. How can you dump all this stuff on the lawn and not effect the tree? I support mulch all the way to the drip and beyond for many reasons not least of which is to try and separate lawn care from tree care.


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## outofmytree (Jun 4, 2009)

woodweasel said:


> The *Acute Hazard Warning Label *on Formulated pesticide products (which usually include inert ingredients) are required to carry an acute toxicity rating by the *U.S. EPA* which is reflected in the warning label on the pesticide container. The U.S. EPA gives a warning label of Category 1 to the most acutely toxic pesticide products and Category 4 to the least acutely toxic pesticide products.
> 
> PAN Pesticides Database @ http://www.pesticideinfo.org/Detail_Product.jsp?REG_NR=06271900487&DIST_NR=062719
> 
> ...



Dithiopyr is a soil residual herbicide used commonly in grain farming. The risk to the public associated with the use of this herbicide in a domsetic lawn when it is correctly applied is minimal at best. 

Whereas I agree that it is important to balance out the use of chemicals in all situations I think focussing on this proven herbicide is a storm in a tea cup. I should imagine that over fertilization of lawns by both "lawnies" and the public is a far greater risk to the tree and people. Ever wiped sweat off your forehead after handling anything with Phosphor in it? Ouch. Don't inhale the dust either. Double ouch.


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## pdqdl (Jun 4, 2009)

woodweasel said:


> The *Acute Hazard Warning Label *on Formulated pesticide products (which usually include inert ingredients) are required to carry an acute toxicity rating by the *U.S. EPA* which is reflected in the warning label on the pesticide container. The U.S. EPA gives a warning label of Category 1 to the most acutely toxic pesticide products and Category 4 to the least acutely toxic pesticide products.
> 
> PAN Pesticides Database @ http://www.pesticideinfo.org/Detail_Product.jsp?REG_NR=06271900487&DIST_NR=062719
> 
> ...



Sorry woodweasel, I don't think you quite understand the terminology. "Acute Hazard" refers to whatever hazard a product might have on a short term or "acute" exposure. An entirely different consideration is "Chronic Hazard", which means the hazard from exposure over a long period of time. Very often people confuse the word "acute" for meaning severe, or extreme; when in fact it has a completely different meaning.

This might help you understand: http://en.wikipedia.org/wiki/Acute_toxicity

I gave you the full, unedited document required by the EPA, and it does not include a single occurrence of the word "acute". Only two uses of the word "category" and neither of those are followed by a number. I don't know everything about what the EPA does, but that terminology is not any part of a product label.

"Warning" and "Caution" are special buzzwords used on a product label that define what *P*ersonal *P*rotective *E*quipment the certified applicator must wear while handling the product. The goal of the EPA is to simplify the education process for the applicators: see "Warning" or "Caution", and you know what to wear.

I am very familiar with the PAN database. They are extensively published, cited, and crosslinked. Unfortunately, they are neither a branch of the government, nor are they impartial in their assessments. Their unstated mission seems to be the reduction or elimination of all pesticides. But I really don't see where you are calling Dimension bad stuff to be around. If it isn't on the PAN database as a "Bad Actor", you can bet that it is pretty benign. I hold their database in pretty low regard, as I have seen their opinions on a number of excellent products with no adverse ecological effects. 

Here is a screen shot from THEIR webpage. Please notice that it is listed in the column of "acute toxicity" as *SLIGHT*, which is the lowest category of risk that they assign.







********************************************************************

By the way, Dimension is an excellent pre-emergent. I haven't used any for several years, mostly because I just don't need to. A bit pricey, it probably leads to a reduction in the overall use of herbicides in a lawn, because it is both a pre- and post-emergent herbicide. By using Dimension, you eliminate the need for MSMA, a decades old popular solution for crabgrass. *M*ono*S*odium *M*ethane *A*RSENATE. 

Which of the two chemicals would you rather have on your yard?


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## computeruser (Jun 4, 2009)

moss said:


> One aspect not covered is that mulching around the tree is theoretically an attempt to provide something like the leafy and woody detritus normally found in forest habitat. It's known that urban and suburban trees with maintained and raked lawn right up to the trunk suffer chronic starvation, the human desire for "cleanliness" and an orderly yard puts the tree at a disadvantage. All I know is I hate seeing mulch volcanoes banked up over the root flare, the mulching strategy has gone haywire in current landscaping practices.
> -moss



100% agreed, based upon research and experience. In a couple parts of the yard where artificial conditions were needlessly pursued by the previous owner of my home, the removal of offending competition - grass, non-native ivy - and the addition of mulch (coarse oak and ash wood chips, shredded oak leaves, a hint of grass clippings) has markedly improved the visible health of a couple of my large oaks previously in obvious visible decline. The tree in one spot is stuck behind a garage, adjacent to a patio, within 15' of my house, and is bounded not 10' away by my neighbor's garage and driveway. It is a twin-trunk white oak, 30" diameter stems and 48"+dbh. 

Digging a shovelful of soil in this one test area previously produced nothing but a clay-like glob of soil when wet, and a mudbrick when dry. After three years, that same shovel of soil produces many dozens of earthworms and other visible soil life (to say nothing for the invisible soil life), obvious fungal mycelia in the mulch layer, and most interesting of all is the fact that the soil microorganisms are able to consume (as in convert 100% to something other than shredded wood) an entire two cubic yards of shredded red oak mulch per year over an area that is 15' x 40'! The soil no longer turns into a lifeless mudbrick, and soil moisture is moderated much better. Just like in the forest. The tree at issue stabilized its decline after year number two and has definitely rebounded this year.




John Paul Sanborn said:


> I would add the caveat that annual mulch additions, especially of the commercial twice ground, can interlock to the point of becoming hydrophobic. I've seen mound plantings that are bone dry under the mulch, even though there is a torrential downpour flooding the yard.



I observed this all the time when I used to dabble in landscaping in my youth. Common sense would suggest that it takes a lot of water to saturate, much less penetrate, six inches of a substance that bears a strong resemblance to sawdust. But hey, at least the weed seeds aren't germinating, right? Heck, I once had a "pro" explain to me that the idea was to trap the water from the spring snow melt under the mulch, as that water was enough to keep the landscape going all year if evaporation could be prevented by a 6-10" layer of largely impermeable mulch...




> From an intuitive level, I like the idea of mulch sandwiching: every time mulch is renewed a layer of true compost is added first.



Anecdotal experience shows this to be profoundly helpful. Even incomplete, unfinished compost makes a superb layering material. Again, based on my at-home test beds, using a sheet composting or lasagna gardening approach to mulching tends to lead to a more rapid improvement in obvious signs of soil fertility than the application of a shredded wood mulch layer alone. Using the presence of earthworms (adults and cocoons), the speed at which partially buried sticks begin to colonize with mycelia, and anecdotal observations of plants growing in the areas, it appears that layering makes a great deal of difference to soil quality and, by extension, improves the likelihood of optimal plant health under the conditions.

I suspect that a similar result could be achieved on a commercial scale by pre-spraying the area to be mulched with compost tea and following up by spraying the surface of the mulch after it is dispersed.




> I think it was Russ Carlson, he did a survey of his yard and found the macrobiota count eightfold higher in soil under the mulch vs a few feet away in the turf.



This has been suggested and/or confirmed by a number of sources. The level of fungal activity that trees prefer, in particular, tends to occur in mulched areas (shredded wood, leaves, etc.) and tends to be difficult to create or maintain in the presence of turf grass.




pdqdl said:


> My point is real simple: I don't see any benefit to the HUGE mulch rings so often recommended by some here at ArboristSite. I can show you many threads where someone mentions a tree problem, and the most often recommended solution is to "mulch to the dripline".
> 
> I still have not heard a compelling argument for this practice, although I certainly will concede that a native woodland setting is self-mulching by default, as the grass has died off beneath the trees.



Benefit or not, it is rarely practical to put a 40' diameter mulch ring on a standard residential lot. Yet it gets suggested the same way that most every small engine problem diagnosis begins with the suggestion that one try a new spark plug. I'd be more interested to know what the homeowner is doing in terms of yard/lawn maintenance, fertilization, irrigation, and what the existing soil composition and soil grade is like. Because you can have a full-diameter mulch ring, but it won't matter worth a damn if you're throwing salt-based fertilizers all over your lawn and yard, providing the trees nutrients they may not need in a form they don't want, and killing off the essential microbial and fungal networks in the soil..





yibida said:


> As someone mentioned earlier, good thread. opcorn:
> 
> I wonder if anyone has performed documented trials on mulching and not mulching trees in a controlled environment during establishment.



I'm sure it has - anyone have good links to research on this?




> Hydrophobic layers of mulch developing are a concern if mulch layers are non permeable to start with (very fine mulch seems to develop this problem). Coarse mulch doesn't seem to do the job as well though as weed growth takes a stand readily.



True, but you can get away with a thicker layer of mulch with the really coarse stuff without undue compaction or reducing air/water permeability. 2" of fine stuff might be too much, but 3-4" of chunky stuff fresh out of the chipper will still allow lots of air and inhibit weed growth very nicely, in my experience. 




> If mulch is applied in a green state and not composted correctly fungal growth develops and adds to a hydrophobic development within layers and the mulch becomes biscuit like over time.



Yes, but this only seems to create a problem with the very fine stuff. Shredded or chipper-chunks seldom seem to suffer from this problem, again based upon my non-professional experience. It can be mitigated somewhat by either applying the mulch over biologically active soil, a layer of compost, or by applying a microbially-biased compost tea mix to the mulch after it has been spread. You will still see the development of mycelia with the larger chunks of wood mulch, but the mycelia will tend to be longer and thicker strands, instead of the denser stuff that forms a fungal pancake layer in the finely shredded mulch. Different fungus will eventually bloom, too.




> I have also read somewhere (sorry not sure of reference) that nitrogen draw down during composting robs the tree / shrub / plant as opposed to sustaining and fixing nitrogen when fresh mulch is used over long periods.



I've read this in a number of books and articles, and it seems correct on a common-sense level. Some reports/research suggest otherwise, though. In any case, I think that this problem, if it is one, is at its worst with finely shredded stuff applied over biologically inactive soil. In the couple test spots in my yard (and now the neighbor's yard, where I'm expanding my "research"), the creation of biological activity in the soil tends to lead to conditions where the mulch is largely consumed within 2 years of application, and a layer of biologically active top soil develops. Subsequent applications of mulches are consumed quickly. I have to believe that the creation of a rich mix of fungal and microbial activity in the top couple inches of soil is far more important to the tree/shrub/plant's long-term well-being than leaving the soil nitrogen alone by not mulching or "mulching" with an inorganic substance.

If one is really concerned about keeping available nitrogen levels up, it would seem that a dusting of alfalfa meal (or a shovelful of alfalfa pellets) or some similar substance could be put down prior to the application of the mulch. The alfalfa meal is a good source of nitrogen that microbes can easily and rapidly access, and it's cheap and readily available, too.




> That said a mixture of a broad spectrum of components that are composted, ie.. leaves, twigs, wood, bark, fruit, etc.. in mulch seems to work better for me rather than an aesthetic one containing one ingredient.



Absolutely believe that. But if aesthetics are required, putting a layer of this broad-spectrum stuff beneath the finish layer of mulch will produce results that appear to be similar to using this mix alone or to applying a layer of finished compost prior to mulching with a single-ingredient mulch. Even a light dusting of shredded fall leaves and grass (as would accumulate in the mower bag when doing a final cut/bag of the lawn in the fall) would put a valuable mix of material down to give the soil and mulch a good jump in the spring.


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## Ed Roland (Jun 4, 2009)

pdqdl said:


> Sorry woodweasel, I don't think you quite understand the terminology. "Acute Hazard" refers to whatever hazard a product might have on a short term or "acute" exposure. An entirely different consideration is "Chronic Hazard", which means the hazard from exposure over a long period of time. Very often people confuse the word "acute" for meaning severe, or extreme; when in fact it has a completely different meaning.
> 
> This might help you understand: http://en.wikipedia.org/wiki/Acute_toxicity
> 
> ...



I hate to divert us off topic with this side bar about chemicals but i did want to respond.

Sometimes I stick my foot in my mouth, too, so i will be gentle. You seem to have looked up the word "acute" and made some assumptions about my use of the phrase "acute hazard warning label". 

Lets go right to the source. Here is what the EPA says "The acute oral, acute dermal and acute inhalation studies evaluate systemic toxicity via the designated routes of exposure." and then guess what... they assign a signal word. Making my use of the phrase "Acute Hazard Warning Label > 2 Warning" completely accurate concerning Dimension turf herbicide.

Here is the paragraph in its entirety taken from the EPA's Label Reveiw Manual. Chapter 7.

"ACUTE TOXICITY DATA. The Signal Word, Hazards to Humans and Domestic Animals, Personal Protective Equipment (non-WPS) and First Aid statements are typically determined by the results of the six *acute toxicity studies* performed with the product formulation. The acute oral, acute dermal and acute inhalation studies evaluate systemic toxicity via the designated routes of exposure." 
-United States Environmental Office of Prevention, Pesticides EPA 735-B-03-001 Protection Agency & Toxic Substances (7506C) August 2003 Label Review Manual 3rd Edition

I hope this helped clear up _your_ confusion about the EPAs use of the word "Acute" and how signal words are determined.

Now, lets get back to mulch vs lawn.


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## treeseer (Jun 4, 2009)

computeruser said:


> I'm sure it has - anyone have good links to research on this?



http://auf.isa-arbor.com/search.asp

just type "mulch turf" or variations. Everyone is an expert when they know ho wto search the ISA journal site.


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## pdqdl (Jun 4, 2009)

woodweasel said:


> ...Now, lets get back to mulch vs lawn.



Ok.


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## pdqdl (Jun 4, 2009)

treeseer said:


> http://auf.isa-arbor.com/search.asp
> 
> just type "mulch turf" or variations. Everyone is an expert when they know ho wto search the ISA journal site.



Nice link treeseer! I am not familiar with that one. In fact, I used the "mulch turf" phrase you suggested and got only one response, and IT WAS A DANDY !

From the following very scholarly document comes the following quote: "Because of greater morning stomatal conductance, daily water use was greater for plants over mulch when compared to plants over turf and bare soil."

WOW ! Who would have thought that *planting grass under woody plants would lead to a net REDUCTION in water loss* for the poor afflicted plants being choked off by those evil monocots!

Check it out for yourself: http://auf.isa-arbor.com/request.asp?JournalID=1&ArticleID=2814&Type=2

I may yet get some of you super-mulchers to come around to my side!

(sadly, a closer read of this article reveals that very few genuine conclusions can be drawn from this article regarding the effects of mulch vs lawn on trees: the plants tested were containerized, they were being tested under water saturation conditions, and they did not attempt to evaluate the long term health of the plants being tested. In fact, at the conclusion of the article, the authors really draw no meaningful conclusions except to compare the relative rates of transpiration of the different bushes tested. The article does a splendid job of demonstrating that turf has many beneficial attributes that contribute to the well being of woody plants; a concept not previously introduced in this thread)


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## M.D. Vaden (Jun 4, 2009)

S Mc said:


> A photo of redwoods and nitrogen-fixing ferns...the ultimate companion planting...check the mulch under *those* trees.
> 
> This thread is specific to turf and grass and the relative size of mulch rings. IMHO a small mulch ring, where it is better than nothing, is a mere physical protection for the trunk against lawn mowers and weedeaters.




The link posted went beyond turf.

In short, trees can have turf beneath if desired, and maintenance can be tailored to meet the needs of that situation.

Likewise trees can be grown without turf beneath.

Hence, it's not an all or nothing issue like the .pdf article that was posted.

In this trade, we need to know how to to both, to be of some cultural value to a community's needs for the broad range of landscape design needs.


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## Toddppm (Jun 4, 2009)

ddhlakebound said:


> The evidence I'd like to see is regarding windthrows and mulching. How many trees could have remained standing if they'd had just a bit more mass to their root system, which mulching would have helped provide?




I'd like to see this too. I've seen just as many windthrows in mulched tree beds as not. Does it make any difference at all? Maybe in richly mulched beds the roots don't have to get as big or long to reach the nutrients they need and aren't as well anchored?


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## yibida (Jun 4, 2009)

*Site Prep*



Toddppm said:


> I'd like to see this too. I've seen just as many windthrows in mulched tree beds as not. Does it make any difference at all? Maybe in richly mulched beds the roots don't have to get as big or long to reach the nutrients they need and aren't as well anchored?



Wouldn't site prep. such as cultivation / deep cross ripping of a soil profile have an effect on root system establishment in conjunction with mulch after planting?


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## Toddppm (Jun 4, 2009)

Should I would think but we rarely do any more than strip the grass or weeds from a site before we make a new mulch bed unless a grade change is needed.


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## pdqdl (Jun 5, 2009)

Ok guys. Lets keep it nice. 

Hmmm. No one seems to have taken up the gauntlet since I posted the note about turfgrass *reducing* water consumption in trees more than mulch.

For those of you who didn't get the jist of the article, or haven't taken the time to read it, it went like this:

The surface beneath a tree does more than cover the ground. It affects the air above it. Mulch, due to it's good insulating properties, causes cooler earth and retained moisture in the ground only. It also reflects more heat upwards than bare dirt, and causes the air above the plants to be drier since there is less evaporation from the earth. Try to keep in mind that the trees live as much in the air as they do in the ground!

Grass, because it absorbs sunlight, allows more heat to reach the earth. It also transpires water into the air, which benefits the tree as well. Much less heat is reflected upward, and so the tree has cooler leaf temperatures and is in an atmosphere of higher humidity. These are benefits that have not previously been considered in this thread.

I think it goes without saying that a forest has little sunlight hitting the ground, so any comparisons of forest/natural mulch with turfgrass are not really valid. 

So guys, where are the lawn bashers now? 
(Still thinking about it I hope!)


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## outofmytree (Jun 5, 2009)

pdqdl said:


> Nice link treeseer! I am not familiar with that one. In fact, I used the "mulch turf" phrase you suggested and got only one response, and IT WAS A DANDY !
> 
> From the following very scholarly document comes the following quote: "Because of greater morning stomatal conductance, daily water use was greater for plants over mulch when compared to plants over turf and bare soil."
> 
> ...




Ditto Treeseer, great link thanks for the info.

Pdqdl I read the information and although I see what your aiming at regarding the resultant water loss from the shrubs there is no mention of the water loss from the turf but the study clearly says that the temperature difference between turf and mulch is generated through transpiration via the grass leaves. This loss of water via the turf MAY balance out the difference in the shrubs and of course the study made no mention of the consumption of nutrients the turf would logically require.

It is worth noting that the soil temperature flux, (I take this to mean the variation in soil temperature throughout the day), was dramatically different under mulch compared to turf. I would like to know whether this more stable enviroment has some positive benefit to the development of useful organisms like mychorrizae. 

More input from knowledgeable people required please.

Something else that occurred to me whilst reading the article was the stark variation in microclimate at .3m compared with very little variation at 2m. This means despite the obvious cooling effect of turf compared to mulch at near ground level, (you walk across either with bare feet at noon!) at the height most ornamental tree branches begin there is little benefit to the tree.

It seems the article does little to promote the benifits of turf compared to mulch when you consider all the information.

I still like a nice green lawn though....


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## pdqdl (Jun 5, 2009)

Like most articles found in that journal, it uses way more arcane techno-speak than is necessary, much too much time describing the methodology, and the conclusions are...inconclusive.

You are right about the microclimate observation, especially about humidity issued. I suspect long wave radiation (infrared) doesn't care about "microclimate" except that it will vary as the inverse of the squared distance: double the distance from the source, and it will have 1/4th the intensity. So yes, the tree branches will be much safer than the shrubs beneath.

Keep in mind, the experiment was only attempting to relate the effect of different surfaces on the plants above them. So they did everything possible to isolate other factors OUT of the equation. This makes it impractical to apply real world scenarios to the date obtained from the experiment.

It's still great to see turf fare well against the mulch.


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## Ed Roland (Jun 5, 2009)

pdqdl said:


> It's still great to see turf fare well against the mulch.



Whats the score. It would be interesting to know what you have found compelling so far.


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## tree md (Jun 5, 2009)

It would seem to me that reduced water consumption in trees over turf would also reduce the tree's potential, unlike trees over mulch where there is more moisture to be consumed and less chance for soil compaction. Just as trees in moister climates (PNW Redwoods or Cottonwoods in river draws of the MW) reach for the sky whereas trees in more arid climates (Oklahoma and Texas) are dwarfed in comparison. But I am no scientist.

Personally, I prefer landscapes with unique natural areas where there are a variety of trees and plants over barren, golf course manicured lots in neighborhoods where every lawn is a carbon copy of the one next to it. I imagine I would prefer the latter if I were into lawn maintenance but the former is more aesthetic looking to me and is better for my business model.


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## John Paul Sanborn (Jun 5, 2009)

pdqdl said:


> Like most articles found in that journal, it uses way more arcane techno-speak than is necessary, much too much time describing the methodology, and the conclusions are...inconclusive.



These are peer reviewed papers, so all the technical stuff is needed. I read the abstracts; then skim the rest.



> You are right about the microclimate observation, especially about humidity issued.....Keep in mind, the experiment was only attempting to relate the effect of different surfaces on the plants above them.



Sounds like this is for new plantings and healing in; I cannot see these effects affecting the environment over 10ft above the ground.

As for the warmer soil, that is a benefit of the mulch. Betula is a good example, the borer susceptible species have a greater incidence of infestation when they have warm rootplates. Photo surveys around Madison Wisconsin, done by UW Madison a number of years ago, found that the southwest portions of hills had the greatest dieback, whereas the norther exposures were the healthiest.


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## D Mc (Jun 6, 2009)

I am posting this link in the hopes of reaching some of you on the importance of what's happening beneath the tree in the living soil. This article reads well and describes the complexities and delicate balances that many people are unaware of. The associations formed beneath turf and trees are different.

I was going to highlight key portions that I felt deserved focus that pertained to the topic of this thread, but found it to have too much good information to only highlight those key points. I will, however, post the last paragraph which sums it up nicely. But please, take the time to read this link in its entirety.

http://www.treedictionary.com/DICT2003/shigo/RHIZO.html

"I believe there is a way to decrease the potential starvation problem. In forests, more wood should be left on the ground, and in cities, more composted wood and leaves should be added in correct quantities to the soil about the base of trees. Incorrect treatments of pruning, watering, planting and fertilizing should be corrected, because they often start the pumps to wobble. If these simple adjustments can be made, rhizosphere starvation will decrease and our trees will lead healthier and longer lives."




It is important to also note that current research has determined that fertilization and application of chemicals can disrupt/disconnect the association of the symbiotic relationship between trees and mycorrhizae. 

Dave


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## M.D. Vaden (Jun 6, 2009)

D Mc said:


> I will, however, post the last paragraph which sums it up nicely. But please, take the time to read this link in its entirety.
> 
> http://www.treedictionary.com/DICT2003/shigo/RHIZO.html
> 
> "I believe there is a way to decrease the potential starvation problem. In forests, more wood should be left on the ground, and in cities, more composted wood and leaves should be added in correct quantities to the soil about the base of trees. Incorrect treatments of pruning, watering, planting and fertilizing should be corrected, because they often start the pumps to wobble. If these simple adjustments can be made, rhizosphere starvation will decrease and our trees will lead healthier and longer lives."



One reason I've encouraged some people out here to have fine compost blown on their lawns in thin layers by bark blowers. But fine compost - not bark. That way it's already more disintegrated.

There are many ways to help the soil and plants utilizing the tools and supplies available.

If you like those images in the page, you might like the site of the USDA mycology team based out here. Has some nifty shots in it.

It's pretty interesting how much is happening below the surface.

The article mentioned leaving woody stuff. I think that more about that aspect can be found Googling "Coarse Woody Debris" or "CWD" + "Forest" - there's quite a few articles online about CWD and forest trees.


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## ddhlakebound (Jun 6, 2009)

D Mc said:


> I am posting this link in the hopes of reaching some of you on the importance of what's happening beneath the tree in the living soil. This article reads well and describes the complexities and delicate balances that many people are unaware of. The associations formed beneath turf and trees are different.
> 
> I was going to highlight key portions that I felt deserved focus that pertained to the topic of this thread, but found it to have too much good information to only highlight those key points. I will, however, post the last paragraph which sums it up nicely. But please, take the time to read this link in its entirety.
> 
> http://www.treedictionary.com/DICT2003/shigo/RHIZO.html



WOW!!! My head is still spinning a bit, need some digestion of that much info, but a GREAT article. Thanks for posting it.


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## Glennak (Jun 7, 2009)

Good artical Alex Shigo has done a lot for the tree industry and the trees by keeping us informed


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## BC WetCoast (Jun 7, 2009)

A lot of people have commented that having a large mulch ring is imitating forest conditons. This is only true in certain forest types. There are may forest ecosystems - temperate rainforest or the boreal forest, where there is a significant amount of shrubby and herbaceous vegetation under the tree canopy. Many places I've worked have had salal up to 7' tall under the forest canopy. 

In the interior dry belt of BC, in the lodgepole pine types, bunch grasses (pine grass being predominant) were the primary understory vegetation.

Even in the southern pine types, understory vegetation is significant or else underburning wouldn't be such a widely used silvicultural tool.

Nutrient cycling is an important consideration here. In the tropical rainforests, material decomposes rapidly and there is rapid nutrient cycling. In the higher elevations of the Rockies, material decomposition is very slow and nutrients cycle much slower. 

The thrust of my comments are - don't generalize.


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## Boa07 (Jun 7, 2009)

BC, you are right the only really simple response to the initial question is as you write don't generalise.

I'm really not sure what pdqdl was trying to achieve with the question and the way it was posed...however there have been a number of very direct and informed responses notably from Guy and JPS.

It is of course up to each one of us to extend our basic understanding of Tree Biology and how it fits into the wider ecology, if we choose not to then fine, but the info is available some of it free, some of it requiring a fee to the authors and the publishers of papers and books....

Being a CA is a start, but that is all it is...the rest is up to you...Shigo laid the basics out for us over 10yrs ago, your own USDA provides excellent primers for soil biology.

There really are no universal solutions for the variety of environmental circumstances and challenges that beset urban trees.....mulch circles have been put forward as a very simple first aid approach to many of those problems, in doing so much of the complex interrelationships between trees other plants and soil biota has been lost.


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## John Paul Sanborn (Jun 8, 2009)

> in doing so much of the complex interrelationships between trees other plants and soil biota has been lost.



That is just the typical urban landscape, which is why I try to recommend other perennials in the mulch ring. 



> The thrust of my comments are - don't generalize.



Generalizations are a start to education; yes, biome types are not really hard and fast, and most of the remnant populations we deal with are all boundary biomes that mix together.

Then there is the speices and regional variety question: for Quercus macrocarpus so we really want to have a mulch ring, or would a prairie planting be more beneficial. Who would weed it out though? These are treatments that need gardeners.

As for the varietal question; if we do not know the origin of the seed stock is it moot? 

My point is that when we are starting off with a concept, then we need to generalize, otherwise the minutiae that may fascinate us will loose the person on the receiving end. Be that the budding arborist, or the potential client.


turf is an unnatural environment, both by diversity and density.
trees and grasses require differing biologies
placing a ring of compost around the base of a tree is the easiest first step to improving the soil around it.

Then again, if we build our business on a few generalities, we will stagnate an be like the landscraper who puts down a 3 inch layer of mulch every year, just because that is what he can sell.


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## M.D. Vaden (Jun 8, 2009)

John Paul Sanborn said:


> That is just the typical urban landscape, which is why I try to recommend other perennials in the mulch ring.
> 
> 
> 
> ...



Actually, there are turfgrasses that are supposed to be able to take care of some soil compaction, in ways that mulch could not do.

So I'll never aim for generalization, but each situation figured out one by one.

The mulch often is the "simplist" though where it will work, which tends to be numerous opportunities.

But as I wrote earlier, turf can be topdressed with compost and recieve plenty of the same benefit for soil improvement from *Glomalin* and *Polysaccharides*.


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## pdqdl (Jun 8, 2009)

I have noticed a trend here among the various participants of this thread, see if you can see it too:

Somehow cultivating and mowing a crop of turfgrass is un-natural. Well, that is somewhat true. Grass naturally grows long and tall, and still can't compete with all those voracious dicotyledonous weeds and trees; the apex predators of the plant kingdom. About the only place grass outcompetes the trees is where naturally occurring seasonal fires burn up the trees. Grass comes back quick, the trees are done for!

Yet all the efforts of the "tree first" adherents seem to think that our cultivation of trees is somehow different. We spray them, we inject chemicals into their roots and their cambium, we trim them to the shape and condition we prefer, we mulch them with our favorite substitute for what the trees themselves deposit on the ground. We pluck them out of the ground and we put them wherever we feel like, and then we give them whatever competition we see fit, instead of what "naturally" grows into the area they grew into from a naturally planted seedling.

I don't see anything more natural about modern arboriculture than I do about modern turf maintenance. Don't even try to pretend that your chainsaw or your mulch is a substitute for nature.

Regarding competition between lawn and trees: why do you huge mulch ring enthusiasts think that turfgrass is any more competition for trees than the other landscape plants that you happily crowd beneath the trees? Ok, I'll admit that a stark bare 50' diameter circle of mulch is less competition than turfgrass, but to what gain? Whoever told you that a thicket of bushes is any less competition for soil nutrients, sunlight, water, than a thicket of teeny little grasses? 

Do you REALLY believe that those evil monocots are killing off the plants that support your livelihood? I personally think that this perspective is a variety of elitism, where YOUR favorite plant is somehow more important than the others.


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## John Paul Sanborn (Jun 8, 2009)

> Do you REALLY believe that those evil monocots are killing off the plants that support your livelihood? I personally think that this perspective is a variety of elitism, where YOUR favorite plant is somehow more important than the others.



Actually, I'm saying that landscaping is unnatural and needs management, as well as education of the owners. My first question of a potential client is "What are your desired results?".

A tree guy who does not understand nonwoody plants limits his ability to serve his clients.



> by Vaden
> Actually, there are turfgrasses that are supposed to be able to take care of some soil compaction, in ways that mulch could not do.





> by Sanborn
> ...perennials I like, especially if they are deep rooting prairie types that will help with water penetration....but that is another thread.



This would include bluestem and the like. Yes the rhizomatous will help as they tiller, but not to any real depth.


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## Ed Roland (Jun 8, 2009)

pdqdl said:


> Do you REALLY believe that those evil monocots are killing off the plants that support your livelihood?



I believe the efforts @


pdqdl said:


> cultivating and mowing a crop of turfgrass


 actually increases my bottom line as an arborist. The damage caused leads to more deadwood pruning, removals and IPM/PHC billing. 
You guys have enhanced my livelihood.


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## pdqdl (Jun 8, 2009)

Watch it there, woodweasel. Don't lump me in with the lawn guys. 

I'm a switch hitter, I go both ways! I must be a prostitute of sorts, cause I charge for my services, too.
(trees or lawn, what the heck, I'll even landscape)

:jester:


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## Ed Roland (Jun 8, 2009)

pdqdl said:


> Watch it there, woodweasel. Don't lump me in with the lawn guys.
> 
> I'm a switch hitter, I go both ways! I must be a prostitute of sorts, cause I charge for my services, too.
> (trees or lawn, what the heck, I'll even landscape)
> ...



Duly noted.


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## teamtree (Jun 12, 2009)

If you have to ask why it would be important to have mulch out past the drip line then you need to look no further than nature. It is not necessarily needed but if you want your tree to be as healthy as possible you would want to memic nature. The mulch will keep the soil moist as well as keep it from getting compacted. The mulch will also add nutrients to the soil as it breaks down. 

I often tell customers that the healthiest trees are found in forests where the leaves fall and remain for the tree to take back at some future point. There is rarely grass consuming the natural fertilizer and no ones is taking the leaves out of the forest. But many times we may be sitting in front of a tree with a nice lawn and the tree is healthy. Go figure. I have not sold too many customers on mulching their yards or leaving their leaves lay. 

Trees are amazing things as we have all seen trees survive and even thrive in some of the most unlikely places.


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## M.D. Vaden (Jun 12, 2009)

teamtree said:


> If you have to ask why it would be important to have mulch out past the drip line then you need to look no further than nature. It is not necessarily needed but if you want your tree to be as healthy as possible you would want to memic nature. The mulch will keep the soil moist as well as keep it from getting compacted. The mulch will also add nutrients to the soil as it breaks down.
> 
> I often tell customers that the healthiest trees are found in forests where the leaves fall and remain for the tree to take back at some future point. There is rarely grass consuming the natural fertilizer and no ones is taking the leaves out of the forest. But many times we may be sitting in front of a tree with a nice lawn and the tree is healthy. Go figure. I have not sold too many customers on mulching their yards or leaving their leaves lay.
> 
> Trees are amazing things as we have all seen trees survive and even thrive in some of the most unlikely places.



I've seen leaves under trees at country clubs. And I'd say that the soil around those compacted far worse than trees I've seen with healthy turf and a decent thatch layer. Well maintained grass should have a small thatch layer.

Where I see leaves in forests, people are not walking around them. In spots where people are walking over leaves in forests, I see compaction.

Leaves also seal gas exchange more.

The mulch scenerio seems far better. We could say that forests have a natural mulch in many areas.

In lawn situations, it's very easy to blow fine compost onto the turf for topdressing to do the same thing, accomplishing the benefits you mentioned.

I enjoy forests and nature too. Because the forest provides inspiration for several ideas.


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## teamtree (Jun 12, 2009)

I am sure you will find exceptions to almost anything you really want to.

Traffic around the base of a tree (foot or otherwise) will cause compaction. Any type of mulch will reduce that but preventing the traffic would be the real issue there...not the mulch (or leaves).

I am not here to argue with mother nature. But since you seem to be taking it in that direction....

Tell me why trees that were in a wooded lot (forest) seem to decline 2, 3 and 4 years after the lot is cleared and then all of the sudden the leaves are taken away and grass is added to the mix. Not only did you hurt the fine roots under those leaves by clearing it out but now you starving trees that were used to a healthy diet. I am sure nature has it all wrong and us humans know a better way.....lol


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## teamtree (Jun 12, 2009)

*just a few thoughts*

some thoughts



M.D. Vaden said:


> I've seen leaves under trees at country clubs. And I'd say that the soil around those compacted far worse than trees I've seen with healthy turf and a decent thatch layer. Well maintained grass should have a small thatch layer.....
> 
> *are you comparing apples to oranges?*
> 
> ...


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## M.D. Vaden (Jun 12, 2009)

> are you comparing apples to oranges?



No - because the example of the forest I responded to was not urban turf either. So the response door is open to versatility.



> but probably not as bad as in a yard where someone mows the lawn each week



The point of comparison would be people walking on leaves in both areas or not doing so. So just as bad if it's happening. It depends on the foot traffic volume - not where it is.



> Ok...i am confused....leaves seal gas exchange more...good or bad?



Why would it be good if leaves lay flat on soil in mats?



> Do you have scientific data to back that up? Most trees in forest are usually healthier than trees in yards...right? Or is that too general of a statement?



In some neighborhoods probably not. In others likely. Depend on the yards. Again, it's a take each yard and each forest zone on it's own. We had a yard with forest-like conditions. Trees were probably even healthier than in the forest, because defects were removed.



> That is a very good point but if the layer is not substantial you will still have compaction issues if you have regular traffic in the root zone.


Do you do stuff that is not substantial?

Not if maintained properly with appropriate thatch. If the mower tires are inflated at low pressure, or if there is no human traffic - virtually nil compaction.

You seem to stereotype forest and landscape situations. Seems that way anyhow based off some statements leaning toward forests=good and landscape=bad. Again, each tree and each landscape must be handled on an individual basis.


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## teamtree (Jun 12, 2009)

Well those are all good points but you came off as a know it all and want to challenge the effectiveness of nature. It sure was hurting before man started ####ing it up......right? Oh...you are saying spreading fine layer of compost to top dress the soil is better...right? 

I want to point out you took my comment about looking at nature as to why people suggest putting down mulch to aid in the health of the tree and turned it into a " not necessarily so" and compared how a mulched country club setting with heavy traffic is worse than a yard with a properly groomed turf with the appropriate layer of thatch. 

So yes...you are comparing apples to oranges in that comparing a high traffic setting such as a country club to a properly maintained turf is not the same thing. Comparing a high traffic area with mulch to a low traffic area with mulch is apples to apples. Comparing a properly maintained turf to a not so well maintained turf is oranges to oranges.

Why mulch out to the drip line? Becuase it is good for the tree, just like nature. As I said before...it is not necessary but it is good for the tree.

Are there alternatives...yes....we believe in vertimulching trees with high compaction issues as well as poor soil environments and it works great. And the customers can maintain a nice turf with little ill effect on the tree as we put the stuff in the ground the trees need to stay healthy. Not to mention the increased movement of air and water. 

I don't know it all and don't care to....but I will try to learn...but I like to see how nature does things and try to stay as close to that as possible. 

And as I stated before, trees are amazing and they find ways to survive in some of the worst situations and environments and despite what man does to work against the natural setting of a tree.


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## teamtree (Jun 12, 2009)

Just some thoughts....



M.D. Vaden said:


> No - because the example of the forest I responded to was not urban turf either. So the response door is open to versatility.
> 
> *What? Are you drunk?*
> 
> ...


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## M.D. Vaden (Jun 13, 2009)

teamtree said:


> Well those are all good points but you came off as a know it all and want to challenge the effectiveness of nature. .



People can get confused if they think that nature can't function in landscape settings.

That's why I pointed out the stereotype scenerio of forest=good versus landscape= bad, which I'm not a proponent of.

Nature can function in forests and in urban landscapes.

Knowing how to maintain trees in turf has been very handy even at our own home. Most of the trees are in mulched areas, but we have some doing marvelously with grass around them. Near nil pesticide use, minimal irrigatioin and good drainage.


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## ddhlakebound (Jun 13, 2009)

M.D. Vaden said:


> People can get confused if they think that nature can't function in landscape settings.
> 
> That's why I pointed out the stereotype scenerio of forest=good versus landscape= bad, which I'm not a proponent of.
> 
> Nature can function in forests and in urban landscapes.



Teamtree's whooped you up one side and down the other and here you are trying to change the parameters of the debate....

It's NOT about being able to function. 

It is about providing the OPTIMUM environment for the trees we're caring for. When is the last time you saw grass take 60 years to start to mature?

Your circular arguments are laughable.



> In lawn situations, it's very easy to blow fine compost onto the turf for topdressing to do the same thing, accomplishing the benefits you mentioned.



LoL~! Topdressing is great, but it simply will not provide all the benefits to the tree (soil temperature moderation and moisture holding) that mulching will. 



> Not if maintained properly with appropriate thatch. If the mower tires are inflated at low pressure, or if there is no human traffic - virtually nil compaction.



I don't doubt that a significant change in tire pressure will result in a much smaller change in the rate of compaction by increasing the contact area, but in reality virtually nobody who's spending time on a mower will run low tire pressures intentionally. Is the guy who owns the mower going to choose to work his engine harder, and burn more fuel, or will he worry about compaction first? Duh....

The laughable part is that you suggest that a sprinkling of topdressing and low tire pressures seem to you to be an acceptable substitute for mulching. 

After all, they can function. 

Can you show us the fake grass again? That was good for a chuckle.


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## teamtree (Jun 13, 2009)

Thanks for having my back.


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## M.D. Vaden (Jun 13, 2009)

ddhlakebound said:


> Teamtree's whooped you up one side and down the other and here you are trying to change the parameters of the debate....
> 
> It's NOT about being able to function.
> 
> It is about providing the *OPTIMUM environment for the trees* we're caring for. When is the last time you saw grass take 60 years to start to mature?



Think you whooped yourself by trying to compare people. This thread is about horticulture.

The *optimum* environment is one of dozens of solutions that we provide for customers, since the environments in most cases are already predetermined. If the solution defeats the client's need for use of space - its not a solution. The most important thing to realize, is that our work does not deal with optimum environments for TREES - our work deals with the *optimum environment for PEOPLE & trees*.

Thats where some people get confused on priorities, by presenting themselves as servants of trees, rather than serving people with solutions and compromises that work long-term.

Many times, retaining moisture is not the preferred option. In our area, some of the oldest and most sturdy trees, like Douglas fir, are ones that don't have moisture retained in the surface area, because they root a bit deeper when conditions dry out in summer - considering Portland had very dry summers. And there is variation depending on whether they are groves or individual trees. Many singles in the country have grass reaching within the dripline.

My own Douglas firs, I don't mulch nor water in the summer, striving for the same long-term durability of other old trees around here. Optimum growth in this region does not mean optimum longevity or optimum sturdiness. We just let them drop the thin layer of needles which does not add up to much more than 1/4 inch.

One of the worst situations I've encountered with trees, was about *40 shore pine* in Aloha, Oregon, due to moisture being retained under several inches of mulch. Half of them tilted halfway during a windstorm here, since we have heavy winds. The damage was due to moisture retention is summer causing surface area root mass. The solution included getting the area to dry out more in summer, reducing the mulch thickness. Some years later, a stronger storm passed through and the trees withstood the wind with no damage. I think a little mulch is fine to get shore pine off to a start the first few years, but not helpful after that.

Again - every tree and person's needs are an individual situation where one-size does not fit all.

Many trees we grow here are not indigenous, so most of the area does not have a *natural* arrangement of plant material.


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## pdqdl (Jun 13, 2009)

I think everyone has contributed a lot of information. Some is anecdotal, some are simple facts based on peoples experience or other published articles, but I think I am the only person who posted references to a scientific study of any sort. Even that reference was completely inconclusive on the topic of my original post, so we seem to have exposed an area for much needed research.

I think this thread needs some summary statements, which I encourage comments on:

1. There is the widely held belief that the bigger the mulch ring, the better it is for the tree. While this is commonly believed, I have not seen any scientific evidence for this. It is certainly true that the further you keep the lawn maintenance away from the trees, the safer they will be, given the quality of most lawn workers.

2. It has been suggested in a couple of articles that there is a greater root density under mulch beds, and less dense roots in turf areas. While I will not deny that this is likely true, how does that translate to improved health for the tree? There is a VASTLY greater root density in container grown plants (or trees planted in root impenetrable soil), but this certainly does not translate to improved health.

In my experience, the general vigor of any plant is related to how far and how deep it roots, not so much as to how "dense" it roots. It is entirely possible that the trees are rooting more densely under the mulch to their detriment, not their gain. It is well known that turfgrass which is NOT irrigated send its roots deeper and invariably survives drought much better than irrigated lawns when irrigation stop orders are issued due to low water supply. Perhaps by encouraging greater root density under the mulch, you might be reducing the trees tendency to seek water, thereby reducing it's survivability during drought (or even localized compaction). I will guarantee that the trees growing in non-irrigated areas survive drought better than irrigated trees once the water supply gets turned off by system malfunction or "stop irrigation" orders.

3. Granted, it is provable that DEEP accumulations of mulch protect the soil from compaction in construction areas. We all know that mulch piled deep enough to protect from construction equipment is not good for the trees either, so let's not use that as an argument for giant mulch rings against soil compaction. 

I think that any reduction of soil compaction by sensible mulch depths of 3"-4" compared to turf are arguable and unsupported. I have driven a lot of heavy equipment through every type of terrain, including mulch beds. NOTHING supports the passage of equipment better than turf except for pavement. (Thick mulch definitely offers greater traction when wet, however) I can assure you unbelievers that if you drive across a yard and venture across a mulch bed (unsupported by tree roots or insanely deep mulch, of course) you will go down deeper into the soil. If you drive repeatedly across wet turf, you end up tearing the roots and working up a trench filled with water & mud. 

4. It is provable that mulch increases soil moisture compared to turfgrass. It is also a scientific fact that increasing the moisture in the soil predisposes the soil to compaction. Hmmm...it would seem that there is a strong argument here that mulch might make compaction _more_ likely by increasing the soil moisture compared to turf. I think it is safe to say that mulch rings will prevent soil compaction from turf maintenance operations, since they won't be in the area at all.

5. Soil compaction from turf maintenance: Clearly an issue with big heavy machines like tractors, not too much of an issue with lawn mowers. So what solutions exist for this? The lawn maintenance folks often do aeration of the lawn surfaces, particularly when compaction is an issue. Rather than suggesting giant mulch rings, I would suggest a better solution: stop any practices that cause compaction (good for both trees AND lawn), and relieve any compaction with aeration.

6. Competition from turf: As requested at my first posting, no one has offered any credible evidence that turf competes unfavorably with trees to their detriment. Comparisons to a woodland setting are ridiculous, because then the trees are competing with each other as well, provably to their mutual decline. All you need to do is look at all the dead lower branches in the forest, the misshapen trees overshadowed by superior trees, and the relative rate of growth to a tree located in a clearing.

There are many examples of allelopathy from trees against other plants, and I have no doubt that some exists in small ways from the turf to the trees. No documentation offered in this thread to support grass as the bad guys.

7. Soil fertility: While it is certainly true that hauling the leaves and branches away during grounds maintenance prevents return to the soil of those nutrients, that is a ridiculous argument favoring mulch over turf. 

The leaves that fall on the ground are not replaced in "nutrient value" by ground up wood. Leaves do not have the same nutrient value that wood does, so they are not exactly interchangeable. Very few people that clean up all the leaves in the turf leave them in the mulched areas, so there is no gain to the mulch area from fallen leaves. On the other hand, there are a LOT of people that chew up the leaves with the mowers and just leave it on the ground. _Net gain for the tree, turf offers the preferred results over mulch on this issue alone_. There are always the people that do nothing with the leaves, in which nature is undisturbed by our actions.

It is well known that mulch often forms layers of impermeable mycelia, which require MAINTENANCE (not NATURE) to disturb and prevent. Although less common, the same thing can happen in the soil, killing off the turf, too. It is also well known that the fungal growth that decomposes the mulch prevents those nutrients present in the wood from reaching the tree until it is all reduced to compost; probably about the same time the landscaper will be asked to rake up all that old mulch and replace with newer, fresher looking mulch. Grass clippings, on the other hand, are more often left where they fall. _Oops._ No gain to the tree while considering leaf disposal by favoring mulch over turf, either.

[Side note: mulch does NOT "rob the soil of nutrients". It does have an absorbing effect on man-made fertilizers because the fungi that are munching on the carbon energy in the wood are starving for nitrogen. Eventually, the fungi decompose too, releasing all the proteins they captured.]

8. NATURE mulches the trees in the woodland, so why shouldn't we in a lawn: This is a silly argument. Since the conditions in a landscape are completely different than in the woods, why do you think that attempting to duplicate one facet of that ecosystem will be preferred over another facet from a different, equally successful ecosystem? One thing is pretty sure: where the prairie meets the forest (naturally growing together: grasses and trees!), the grass is growing under the trees (unmowed) and the trees have a completely different shape than they do in "the woods". Not surprisingly, this shape is what we see in our landscapes, rather than the tall, no-lower-branches, top heavy trees that are found in the forest.

I don't recall ever noticing the mulch under any prairie trees I ever walked around under, either. What I did notice was reduction in the height of the grass and a trend toward other varieties of plants at the base of the tree. 

9.Erosion: When the pioneers came west across the plains, they found deep soil and very thick sod. The depth of the topsoil had accumulated over millenia, and has since been shown to be diminishing with each passing year of farming. So the soil building characteristics of grasses are well known. Unfortunately, I am not aware of any information that documents the relative rate that forests "build" topsoil. I can guarantee that turfgrass is vastly better at erosion control than mulch, since I have never seen a mulch layer stand up to running water, whereas turfgrass is better than many erosion control products sold, once established. It is pretty well understood by even the giant mulch ring proponents that once the landscape trees have eliminated the grass, soil erosion occurs and the tree roots are exposed. Their solution: add mulch! Why not add topsoil and a better erosion control product...say turfgrass?

10. More on different ecosystems: The prairie is mostly found in areas where there are two prevailing conditions: relatively low rainfall and alluvial soils that hold water. Where there is less water,you don't get sod, you get sparse collections of hardier species of plants, both clump grasses and tougher woody plants; when it really gets dry, you get cactus. Where there is only rocky soils (and sufficient water), you get trees and forest; almost no grass. Where there is lots of water, you only get forest. The grasses are only able to compete with the forests on two areas: they do survive pretty well in climates that have an unpredictable water supply, and they can survive fires. In fact, the prevalence of prairies is almost exclusively attributable to periodic drought that encourages the fires that kill off the trees. Too much rainfall, the trees take over. Too many fires, the grasses have free reign over the land. Even in forested areas following a fire, the grasses and soft stem broadleaves move in first, then get whipped later by the trees.

Where do comparisons to prairie and forest ecosystems fit with our concerns over giant mulch rings? They don't. Neither prairie nor forest really match the conditions of the modern landscape, so arguments that draw conclusions based on facts drawn from one setting and applied to another are likely to be flawed.


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## pdqdl (Jun 13, 2009)

I am very pleased that this thread has had so much participation. I wish that everyone could spend more time trying to understand the opposing viewpoints, and less time wasting their efforts in silly egocentric arguments.


I hope that anyone who actually manages to read my previous, terribly long post will take the time to let me know what they think about my comments. Please! Just because we see things differently does not mean that we cannot learn from the other persons viewpoint. 

I have diligently looked up every reference quoted in this thread, and I am more knowledgeable now for that effort. In some cases, I even got a tiny bit closer to making some giant mulch rings.


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## teamtree (Jun 13, 2009)

Just like most other threads on this site when someone makes a point someone usually comes on and trys to disclaim that point without really discussing the initial question at hand. 

MD could have said good point and left it at that but he tried to tell us that my point was wrong. I made the statement as to you only need to look at nature to see why a mulch ring out to or past the drip line would be a good idea. 

MD do you not agree with that statement? You then tried to compare a country club with high traffic as to why mulching is not a good idea. In which, the mulching was not the problem...the traffic was the problem. And in that particular case, mulching was still better than not mulching.

MD continued to try to make myself look stupid for suggesting nature had the right idea and started giving examples of things that really did not have anything to do with what this thread was about. 

Why do you mulch? He never really ever said anything to give a good point on that. He proclaimed how a properly maintained turf would serve the tree well. Which again, had nothing to do with the initial thread starter question. 

He can say what he wants about me and my thoughts if that makes him feel better. But please, if you want to debate about something at least keep on topic.

I even commented how he made good points for other situations but nothing he said really addressed the question at hand.

In the future, a "good point" or "interesting thoughts" would be just as good as putting someone down.


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## teamtree (Jun 13, 2009)

pdqdl....you make some great points.

And as MD pointed out as well...there are so many different scenarios in landscapes (turf, woods, forests, parks, flower beds with trees, etc. etc.) that we all deal with and in many cases trees suffer in some manner or another and we as arborists are called upon to solve those problems. 

I don't think that mulching is the answer to all tree & turf issues. I simply believe it is good as it is as close as nature as we can get. I have suggested mulching thousands of times and people laugh at me when I tell them how much area a good mulching bed would take up. Some people love their grass more than anything. Are there other solutions....absolutely and it starts with good turf and soil management. We are no different than you, MD, we solve problems for our customers and treat each scenario differently. But I can say without a doubt, mulching is a good idea and it is a good idea as it duplicates nature. It is not the answer to all turf and tree issues. 

It really was not a remark in which there is any debate. It is my opinion and you can like it or not. If you want to debate it and argue it...that is fine. But just stay on point MD.


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## M.D. Vaden (Jun 13, 2009)

teamtree said:


> Just like most other threads on this site when someone makes a point someone usually comes on and trys to disclaim that point without really discussing the initial question at hand.
> 
> MD could have said good point and left it at that but he tried to tell us that my point was wrong. I made the statement as to you only need to look at nature to see why a mulch ring out to or past the drip line would be a good idea.
> 
> ...



Transition from the personal level to the horticultural, here are a few more ideas folks.

We have flat areas and hill areas here around Portland and Beaverton. I've encountered dozens of yards where the slope is just enough for water to wash mulch all over the place in autumn, winter or spring.

A bad choice mulch would be for those.

Each yard and each tree need to be evaluated on an individual basis. And the ENVIRONMENT is the environment of people and families and trees, not just the environment of trees.

On a slope where mulch can wash, but not too steep for mowing, turf can be the better solution. Other times, durable shrubs planted like a tall ground cover are a good option - like pygmy barberry which does pretty good with minimal water. If the foliage covers over, mulch is not essential, and the fallen leaf litter may suffice. In a sporadic erosion area that is.

Groundcovers may also work well, like Vinca, St. Johnswort or Pacchysandra. In time, ground covers could hold mulch, if the tree needs it.

Let us not just look at nature alone, but all the solutions available.

Whenever big mulch rings are employed, we not only gain benefits, but a different style of maintenance. The mulch rings can be very good for the trees. Then we merely need to tell the property owners how it changes their maintenance.

1. If it's a big leaf maple dropping thousands of viable seeds - will the seedlings be handweeded?

2. Will handweeding lead to extensive labor costs? Or will it be inconsequential?

3. What about pesticides then?

4. If pesticides - why was this maintenance path chosen?

I recall some comments by others about landscape maintenance people and damage to tree trunks if turf is near the trunk. Around here, another concern would be homeowners and landscape maintenance people applying herbicides around trees. Few arborists I know of undertake the responsibility of weed control chemically. So the handweeding would be one other alternative independent of spraying, and dependent upon will or finances.


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