Root Pruning

[ROLLACOSTA]

Quick question ,how many of you out there are offering root pruning as one of your service's ??...One other question if you root prune a tree surely you must also carry out a crown reduction at the same or near the same time or the tree will eventualy be left with lot's of dead wood in the crown ???

Lastly if you carry out root pruning do you get the client to sign a disclaimer as this type of work is not an exact science ??

 

[Ekka]

Hi

That's a big no on canopy pruning when you've done the roots! NO no no.

Also, what sort of root pruning are you doing?

Is it grinding down surface roots, or putting a barrier, or trenching, or tunneling? How are you cutting the roots?

Also how far from the trunk? I need to know the trunk DBH and in your estimate how much root you are removing & how far away from the tree?

 

[treeseer]

I agree with Ekka; I reduce crowns on newly planted trees that required removal of major defective roots, but on a bigger tree I'd wait for dieback to start then seek to head it off, no pun intended.

a disclaimer is a good idea.

Do you foreigners get Arborist News? Here's a portion of an article from the last issue that dealt with pruning girdling roots. Forgive the literary excesses. Article copyrighted by ISA I think.

The pair of Magnolia grandiflora were planted in the 1940's with the dream that they would bring not only grand flowers but a solid gleaming green canopy to grace their front yard. In the early years they grew toward fulfilling that vision, a pair of adolescent beauties that were the envy of the neighborhood. But some years later, just as they should have been delivering on that promise, she noticed that one of them started looking weak on the side away from its twin.

The change was subtle at first. The green in the leaves wasn't so deep and glossy, and their size was smaller. Then some leaves dropped, and barren twigs in the tips over the lawn began to show. Her yard man couldn't put his fingers on the culprit. Her arborist had a hunch about the perpetrator, but had no plan to knock it out of commission. Each year the magnolia looked a little worse, until she couldn't stand it any more.... I tested the trunk and climbed the crown, searching for signs of some kind of disease infection or insect infestation. I assessed the soil to see if there were enough nutrients and air and water. I poked around the outer roots, looking for fungus or drought damage or trenching or compaction or signs of silent, allelopathic battles with the turfgrass. Then I finally looked where I should have looked first, and saw what was crimping this tree's condition. A possum named Pogo had the answer, in a comic strip long ago.

What did the Dendro Detective see?

(Turn page, show second picture) Pogo said, "We have met the enemy, and he is us". This magnolia's magnificence was being robbed by the stranglehold its own roots put on the trunk, squeezing so hard it was stopping the circulation. I could see small roots lapping over buttress roots above the soil surface, so I swiftly solved that problem with my trusty loppers. It was time for a root collar examination, so I shoveled away some soil and found deeper roots wrapped around the trunk. That's where things got real interesting--the squeeze was the tightest on the same side as the dieback in the top. In past cases I’d seen that oak branches are nourished by the roots right below them--could it be that magnolias are also ring-porous?

Some books say that you can do more harm than good by removing big girdling roots. The tree needs roots for uptake, and it's hard not to wound the trunk while removing them, so they say it's best not to disturb them. First do no harm, as that Hip Greek said. But the thought of this southern belle spending the rest of her years watching her beloved magnolia slowly strangle itself was more than I could stand. I had to do something, but what?

I took a page out of the pruning book, and figured that if I limited the dose of root pruning to 20% per visit I oughta be OK. First with chainsaw, then handsaw, hand pruners and finally with hammer and chisel I sliced out three root sections. My nerves were frazzled by the fear that I'd gouge the trunk, or the bark on the roots would be stuck to the bark on the trunk, but the root sections came off clean with a "pop!". I think I saw the trunk tissues gratefully swelling out as the circulation came back, but I mighta been imagining things. It had been a long day. The next problem was, how could I tell what percentage I just took off? Branches you can see, but with roots it's a guessing game. I decided to call it quits before attacking the biggest girdler.

My plan is to come back in late winter to aerate, inoculate, fertilize and mulch the soil, to stimulate root function out around the dripline. Then next fall I'll return with the weapons and cut away some of the worst misguided roots that are putting the squeeze on my client's assets. Each year I'll check to see that the roots don't get any funny ideas about growing back over the trunk. If they do, they're gonna get it good. After a while I figure my belle can watch her magnolia grow again instead of dying a little each year.

Relief replaced the strain around her eyes as I told her the plan. She told me to come back when the time was right, so I packed up my gear and drove the old pickup back across the tracks to my crib. I scrawled a reminder on the March page of my desk calendar to frazzle all the big roots on every tree that I ever plant, guiding them straight away from the trunk. I’d hate to see the next generation of Dendro Detectives frazzling their nerves when they're forced to chisel girdling roots off a trunk just to stop a tree from strangling itself. Instead they should be coaxing the beauty out of trees, and making their clients' dreams come true.

 

[ROLLACOSTA]

I was talking in general,obviously the further away from the trunk the better for root pruning,Ekka i was thinking i suppose more on the lines of root pruning for the instalation of a root barrier ,as for the way i would root prune i would think it's much the same as pruning branches nice clean cut's etc ,is there a formula for calculating distances for root pruning ie DBH then distance etc ,i know that the bigger cut's you make the more root area you have killed so i would be thinking on mature tree's 2-3' is maximum diameter for cutting.I would love to be able to go on a course relating to this subject unfortunatly there hard to come accross over here

 

[ROLLACOSTA]

surely the crown dies ,when root's are cut ? leaving lots of dead wood !

 

[Ekka]

Hey Rolla

I'm on a constant education deal this year, this seminar was an extra, I paid $4000 for latest private education package, and so far on top an extra $750 for these extra's, and that's just this year ... why?

Because I'm sick of the BS. Sick of the opinionated, self professing ******s who write crap and believe it. I want facts and latest info, I've always been like that, and when a client gets me they get the real deal.

Anyway, back to the roots.

Yes, roots work just like the branches of the trees, good clean cuts required and the smaller the dia of the root you cut the better, less than 4" dia preferred, the further from the tree the better, they epicormic just like branches and CODIT as well. Might be tougher to find collars though!

Straight out of the book, Critical Root Radius CRR is DBH x 1.5 in feet

example, DBH is 20" x 1.5 = 30 feet

is usuallly further than the drip line.

If more than 40% of the roots were cut you have destabilized the tree. Do not to cut more than one side and preferably do not cut the windward side as roots work under tension like ropes.

Deal with any die back later and only prune off the die back.

I also now have a chart of species with their tolerance to root pruning. So what's the tree?

 

[Kneejerk Bombas]

Why are you root prunning? Is it to invigorate the tree after thinning?

 

[ROLLACOSTA]

I don't have a tree to root prune at the moment i'm just asking you guy's your opinions on the subject ,as it's hard to get much info on the subject over here ,thanks EKKA and guys for your advice /input

 

[ROLLACOSTA]

Are there any good book's/publications on the subject ??

 

[ROLLACOSTA]

EKKA and guy's do you sell root barriers [instalation service]

 

[Ekka]

I don't but refer it on. They charge $45 per linear metre.

You need a water cutter, generally they go down 600mm. Pretty messy work.

 

[ROLLACOSTA]

a water cutter please ,elaborate what the heck is a water cutter??

 

[Ekka]

Extremely high pressure water jet, 30,000 psi, will cut straight thru roots, pipes, steel and body parts! This is the cleanest, fastest and safest way, the company also does a lot of transplants and found root damage was minimized with this equipment.

The nozzel can be varied but will cut approx 12mm wide like a lazer.

 

[MasterBlaster]

Why are you root prunning? Is it to invigorate the tree after thinning?

Haha! So, wtf is root pruning? I've heard of it concerning bonsai, but that's about it. Please, school this noob.

 

[Treeman14]

Dang, Blaster. Look down once in a while would ya? The roots are those thingys you trip over before you spike up the tree.

Seriously, you've been in this biz for how long now and you've never heard of root pruning? I think you're pulling our proverbial legs, but I'll give you the benefit of the doubt. Most of our root pruning calls are from homeowners who have tree roots uplifting sidewalks, driveways, or foundations. (We can start another thread regarding the debate about root uplifting versus soil subsiding, ok JPS?) We go in with a Dosko root pruner, kind of a cross between a stump grinder and a ditch witch, to cut a trench 12" to 24" deep, severing the offensive roots. Then we either install a root barrier or just fill in the trench, depending on the client's budget.

There was an article just recently in one of the trade mags about treating root pruning more like crown pruning, actually exposing the roots and making proper cuts back to laterals, etc.

 

[Ekka]

Hey Treeman14

Yeah, there's some guy over hear getting around with this big vacuum sucker thingo that washes away the soil and sucks it up into this tanker truck exposing the roots. Doesn't damage the roots.

He's trying to get the builders etc to convert from trenching to this machine as he can suck out a 6' deep trench without breaking roots and you can slide the pipe in ... but like usual, he's going broke because no-one gives a crap about the trees roots.

 

[Treeman14]

Yup, I hear that. We were pruning trees for the developer of a large apartment complex. Another contractor was hired to install retaining walls around some big live oaks in an area where they were lowering the grade. He used a backhoe to do the root pruning, making a five foot cut about eight feet from the trunk all the way around. The trees died; about six months after the project was finished and the developer was long gone.

 

[MasterBlaster]

I'm just a mere climber...

I rarely cut roots.

 

[Dadatwins]

Any opinions about skimming roots for sidewalk installation? After the cement is lifted and dirt removed, I have skimmed down roots a few inches to allow for sidewalk replacement. Factors to consider include the amount of root diameter that must be skimmed. Think this might be a better solution than the backhoe or tree removal. What do you think? Agree no pruning of live growth on the tree after root pruning.

 

[treeseer]

Any opinions about skimming roots for sidewalk installation? After the cement is lifted and dirt removed, I have skimmed down roots a few inches to allow for sidewalk replacement.

Earth to Dada: Roots Grow!

Second Revelation: Wounded Roots Rot!

Here's the frontpage article from the last issue of the ASCA newsletter, on this very topic:

"It was a wet and windy day. Dad sat idling in his SUV in the line in front of the school, waiting to pick up his child. The next time he saw her, he was in the hospital. A gust had toppled a sugar maple, crushing his car and his back. The town’s insurance carrier asked me to determine whether a visual inspection of the tree would have found any defects that could have been acted on. I was also assigned to evaluate the town’s tree risk management policy, and to propose a program of due care of public trees.

The photograph showed that the roots that lifted out of the soil in a line parallel to the sidewalk were all dark in color. No living root growing toward the sidewalk was evident. This indicated that the cutting of roots and resultant decay during sidewalk replacement resulted in a loss of stability.

Other visible defects included a root repeatedly damaged by the county’s mowers, a canker on the trunk, and an extremely imbalanced crown, weighted entirely over the road. There was no stump to speak of; the tree had been supported by bark and a few strands of cellulose.

I reviewed the site conditions with the public works director, who told me the sidewalk was replaced six years before. Deadwood was pruned a year before the casualty, but since the leaves were in good shape, the tree was judged to be healthy. The town’s tree contractor often phoned in reports of public trees that were in need of maintenance for “safety reasons”; some were removed due to a slight trunk lean. Even though he advertises tree topping, his company appears to be above average for the area.

To determine due care, other towns’ policies were reviewed. Pruning roots when sidewalks are replaced is common, but there was no record of a similar failure.
Many towns had a more proactive way of maintaining their green infrastructure, from cities with urban foresters to towns just as poor as this one that made the effort to become Tree City USA’s. Trees and other infrastructure present assets and liabilities to their owners. Considering both together can preserve the value of nonliving elements such as sidewalks, and increase the value of growing elements such as trees.

AFTERMATH
The town’s insurance company reviewed my report, and paid the driver’s claim without question. Sovereign immunity was not asserted; lack of due care was unquestioned. An affordable program of tree management was proposed, and high on the list of changes was methods of sidewalk repair. With the publication of ***Reducing Infrastructure Damage by Tree Roots--this is a good book and cheap--~$20.*** ( synopsized by Dr. Costello at the 2004 ASCA conference), towns are looking more at other ways of managing pavement near trees. Creatively merging the green infrastructure with the gray, many strategies for resolving conflicts between mature trees and sidewalks are detailed in this book. In order of impact they are:

1. Remove old panels. Install a new sidewalk of packed stone, asphalt, pervious concrete or concrete curved away from buttress roots.
2. Remove old panels. Bridge buttress roots with packed structural soil and sand under fabric. Install sections of recycled rubber, asphalt, bricks, pavers, pervious concrete or concrete above. (If concrete, reinforce with fiberglass rebar, wire mesh, or standard rebar)
3. Leave heaved sidewalk in place and make the surface smoother by either grinding down the lifted edges or making ramps.
4. Remove old panels, prune roots, and install new panels at original grade.

When liability and replacement cost are factored in, strategies #1-3 cost less, but #4 is still by far the most common in our area. I hope I never get another call like this one, but as long as sidewalk installers cut roots, more losses are inevitable."

This was the first thing i talked about at Midatlantic ISA's Field Day last Sep in Byrd Park, right near you. You musta missed it. hope you missed hte indoor one too; it wasn't so hot. I met a guy form the City of Richmond at the Field Day and he said he read the book and passed it on. And Richmond is still grinding roots?

That's surreal, Dada!