to mulch, or not to mulch

[topnotchtree]

As a line clearance trimmer I will not pretend to know the biology of the business, but I thought mulching around trees was a good idea. I have some ill looking mature trees on my property so I thought I would give a tree doctor a call to see what could be done. I recently planted 10 trees thruout my yard and used woodchips from last year to mulch around the trees. Approximately 2 to 3 inches deep. He said the chips were robbing the soil from needed nutrients. Is this true? He also said the nursery I bought the trees from, who I have been happy with all along, didn't know squat about trees. I dont like dealing with people who bash other peoples businesses. Any thoughts?

 

[rumination]

Don't know about the nursery, but the claim that the mulch/wood chips is robbing excessive nutrients from the soil is totally bogus.

 

[topnotchtree]

This guy claims to be a graduate of arborcultry. Not a certified arborist. I do understand green chips emit nitrogen, or something that is not good for delicate rooted plants. That is why I used last years chips. The young trees I mulched seems to be doing fine. I have a few mature trees looking ill that I would hate to lose. I think I will get a second opinion. Thanks for your input.

 

[topnotchtree]

The guy showed up today while I was at work. He talked to my daughter who was here. He was supposed to talk to my wife on the phone to discuss options, but she is not home yet. I just thought the mulch theory sounded like a bunch of malarky to me. I will let you know what his suggestions are as soon as I find out what they are.

 

[TheTreeSpyder]

i think that trees naturally want about that much mulch; and will try to wall off a biospere area that would have rich mulch in it, cool temperatures, dampness to foster more lively soil. i think a tree's root crown will nature-ally ramp/serve the mulch away from the trunk in this process millions of years ago.

i think we can learn more from millions of years of evolution,than teach it. i think we should assume that even though so large, a tree has no real spare parts, everything is streamlined to the path of least resistance for growth vs. function. {See Large, Protected Feeding Territory Thread }i think we should give trees as much of what they were designed to have as we can bear to forfeit. If we must raise the branches so that it can't keep, cool and protect it's own mulch, perhaps it would be best if we replaced as much as possible, what we have taken. The system was designed to be complete with recycling; in fact dependant on it; as any other 5 million year old crutch that it had gotten used to to feed the largest life ever; as efficiently as possible, things serving many functions at once.

i think that people's imagery and Quality Identifiers (thread) of work should be changed to being able to have a large piece of Nature like a pond in the yard, that goes by a delicate balance and supports all kinds of life, or all but crumbles.

See Also:
Shigo Book Choice Thread

Or, something like that,
:alien: :alien:

 

[Guy Meilleur]

If your old trees are looking ill, they have had problems for a long time. Good to get an expert in, smart to consider the below-ground portion of the trees first. I also don't like pros that bash other pros, and agree that the mulch is not harmful.

Scratch your soil. Do you see many roots in the top inch? If so your soil is eroded, and even deeper mulch may be a good idea. How wide? Beyond the branch tips is ideal.

http://www.treesaregood.com/treecare/mature_care.asp
http://www.treesaregood.com/treecare/mulching.asp

Check to see if your young trees were planted right:

http://www.treesaregood.com/treecare/tree_planting.asp

 

[ROLLACOSTA]

how compacted is the soil around your trees ,this week weve taken a few trees down and im sure the reason they died or declined was due to compaction

 

[JeffE]

a lurker speaks...

I sincerely doubt that this is a problem with your trees, but maybe the tree "doctor" was concerned not with the amount of mulch, but its composition. Mulch with a very high C:N ratio can sometimes cause nitrogen draft, a deficiency that occurs when soil microorganisms, quickly proliferating due to the excess Carbon, immobilize all the Nitrogen, so it's unavailable to plants. Trees like the organic matter incorporated into the soil to be 25:1, while wood chips are usually around 700:1.

In most cases this is only a problem when the mulch is both high C:N and small particle size... something like sawdust or fine chips, so they're quickly incorporated into the soil. Large wood chips are unlikely to cause such a problem, and there are so many other benefits in terms of moisture management, improved aeration & structure of the soil, etc.

If one is concerned, I would think that adding a thin layer of compost beneath the mulch layer would take care of any C:N issues.

 

[Kneejerk Bombas]

Mulch can be good or bad. In most cases, I'd say it's bad.
The reason is that in most cases it's the wrong type of much or it's installed wrong.
How are you going to deal with the existing grass? Scrape it off with a skidsteer? Poison it with Roundup or other herbicide? Put the mulch down 6 or 8 inches deep? I hope not!
Would it surprise you to know that many landscapers would do all three things!

When a person has a problem with a mature tree, first I look at obvious problems and try to solve them. Meanwhile I do a soil test. While waiting for the results of those, I'll try to remove stresses from the tree by properly mulching, watering during drought, adjusting pH, etc.. Once the soil test comes back, make any needed adjustments.

The idea of mulch is to create an environment similar to a forest floor. Roots like cool moist conditions, with plenty of organic matter, which can break down from biologic activity. This organic matter becomes compost, a delicious healthy treat for the trees.

There are benificial fungus that exist in a forest soil that are often in very low populations in urban soils due to low organic matter, compaction, temperature extremes, and the presense of thick grass. The fugal spores are there, they just can't grow because the conditions are not right. Without these Mychroizal fungus, mature trees just don't do well.

 

[SilverBlue]

Don’t think that mulch will instantly solve problems either, it takes years for soil structure as well as the very diverse community of soil life that it contains, keep in mind that fungi are also among the first organisms to begin carbonaceous decay and they are very slow.

Mike, compost is only one stage of the decomposition process leading to humus, however in natures real world it’s a continuous process from life to humus, man has never or will be able to replicate the complicated process either synthetically or with the half azzed approach of mulch or compost addition.

JeffE, soluble nitrogen or nitrogen fixing bacteria problems typically occur when high carbon is incorporated into the soil’s top few inches- not just laid on the surface, especially in synthetically treated or unfertile soil, oxygen deprivation is more of a serious problem. While compost has it's benifits, the microbial content is not optimised due to the materials used in said compost, not to mention that improperly made poor compost can do more harm than good.

 

[Kneejerk Bombas]

Originally posted by SilverBlue
man has never or will be able to replicate the complicated process either synthetically or with the half azzed approach of mulch or compost addition.

It is an immediate improvement over lawn though.

Originally posted by SilverBlue

While compost has it's benifits, the microbial content is not optimised due to the materials used in said compost, not to mention that improperly made poor compost can do more harm than good.

Could you expand on these thoughts?

 

[John Stewart]

2 to 3 inhes of last years mulch is not a issue!
6 inches big issue!
Last years chips won't deplete nitrogen but there could be other pathogens in it like if the tree was covered in black knot and you chipped it up and then mulched a ornamental cherry
Your mulch is not the problem!
John

 

[TheTreeSpyder]

i think that we can learn more from Nature,than teach it; and the Nsture-All way would be for the tree singley or in wooded areas to have it's own mulch, and jealously protect it as in Living Large - Taking Large Territory - to Feed Large Thead; so therefore mulch is better. Nature moves slow and carefully, experimenting some to best efficiency as a unit and total design. With millions of years to calculate this; we can prolly save a lot of time figuring and go follow the Leader!

Any data on the effect of de-naturing mulch in dyeing it etc.?

No need to feel short changed, jest my 2 sense.....
:alien:

Happy 4th Display, Click sky lots of times

 

[JeffE]

JeffE, soluble nitrogen or nitrogen fixing bacteria problems typically occur when high carbon is incorporated into the soil’s top few inches- not just laid on the surface

Right, which is why in the case of mulch, C:N is unlikely to cause problems except when the particle size is small, and thus more quickly incorporated into the soil through natural processes - small meaning less than 9mm. See Carlson, CR. 2001. Mulch, Part 1: Too Much of a Good Thing Can Be Bad. Arborist News 10(6)

man has never or will be able to replicate the complicated process either synthetically or with the half azzed approach of mulch or compost addition.

Agreed. However, what separates arborists from foresters is that the former is usually forced to manage forest species outside of the forest. Thus compromises are necessary. Mulch and compost is a much better compromise than turf, as Mike said, when trying to mimic the soil surface environment that the tree is adapted to.

 

[Kneejerk Bombas]

A huge advantage to mulch is the reduced compaction, because people, lawnmowers, and other traffic tend to stay off chip beds.
The chips can also reduce compaction to the soil by spreading out the load, when there is traffic on them.

 

[Stumper]

Topnotch, I think that your "expert" suffers from a common ailment (I've had it too)-" A little knowledge is a dangerous thing". Nitrogen robbing during the decomposition process of wood chips is real science- But his knowledge is incomplete. This is one of those occasions when practical experience and good observation skills beats rudimentary 'book-larnin'. (In fairness there is balanced imformation in print-the problem is that "Nitrogen robbing" is one of those things that people latch onto for test taking and instant "expertise". Mulch them!. Other ammendments to the soil may be beneficial also so get it tested.

 

[SilverBlue]

Originally posted by Mike Maas
It is an immediate improvement over lawn though.





Could you expand on these thoughts?

What I am getting at is that not all compost is created equal, poorly or improperly made compost can be unfinished –wrong C/N ratio to more serious problems such as high pathogen count due to anaerobic conditions. There is also the complex interaction of the microbe community and introducing foreign microbes into the specific soil, one example being using generic compost manufactured from vegetable waste or mass collected city curbside collection, these end products do not resemble what can be found say in natural forest soils, one may introduce foreign microbes that dominate certain naturally present organisms upsetting the natural balance. Take time to compare different types of compost sometime, especially take the time to explore a forest floor and study the composition and the life in the soil. Then compare the urban landscape soil that trees have had to adapt to.

 

[SilverBlue]

Agreed. However, what separates arborists from foresters is that the former is usually forced to manage forest species outside of the forest. Thus compromises are necessary. Mulch and compost is a much better compromise than turf, as Mike said, when trying to mimic the soil surface environment that the tree is adapted to.

Mulch and turf should not be compared, either compare live plants that form a natural symbiotic relationship or compare man made mulch methods to the natural mulch of leaves etc in nature.

Trees adapt very well to all landscapes from grasslands to mountain/ rocky land. However nature provides what man typically does not

 

[JeffE]

Mulch and turf should not be compared, either compare live plants that form a natural symbiotic relationship or compare man made mulch methods to the natural mulch of leaves etc in nature.

I get what you're saying. However, in this case the comparison is valid, because mulch is an alternative to turf or bare ground in the urban landscape; rarely would it be feasible to actually recreate the true conditions of the forest floor under a street or landscape tree. I think we'd all agree that a naturally developed soil and understory rhizosphere is almost always superior to that found in areas developed by humans.

Trees adapt very well to all landscapes from grasslands to mountain/ rocky land. However nature provides what man typically does not

As long as we're quibbling It would be more correct to state that trees, as a group, have adapted very well to many different landscapes. However if you put a bald cypress on top of a mountain in the rockies, it would be unlikely to adapt. Many of the species arborists deal with as individual trees in the urban landscape would find their ideal environment in forest systems. Again, I think everyone would agree that this fact should be considered when caring for their health.

Just for the record, I wanna repeat that I don't think the C:N of the mulch is a problem for the original poster; I was just suggesting that it might be what the tree doctor was thinking.