Arborists Know Veteran Tree Management

Guy, thanks for posting.

Were these your words?; "We prune far too few, and remove far too many trees". I remember you saying something to that effect at our New England Chapter Conference in 2013. The sentiment really resonated with me, but the actual words didn't really stick...
 
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Guy, thanks for posting.

Were these your words?; "We prune far too few, and remove far too many trees". I remember you saying something to that effect at our New England Chapter Conference in 2013. The sentiment really resonated with me, but the actual words didn't really stick...

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Actually that was a Gilman quote; I'm only s reporter, and you remembered accurately.. “In Sweden, 600 to 800 year old trees have been reduced for hundreds of years.
4 or 5 foot trunks-some even larger - with 4 inches shell wall.
We remove too many trees and prune too few!“

And the quote from 2010 Biomechanics Week. Dr. Ed Gilman: “We looked at one 10” planetree with a large hole or ‘defect’, and figured it would break straight away from the four-ton winch.

Another 10” planetree had no visible ‘defects’, so we figured the trunk would hold strong, and that tree would uproot instead.

But the exact opposite happened!

We know next to nothing about tree biomechanics.”
 
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And the quote from 2010 Biomechanics Week. Dr. Ed Gilman: “We looked at one 10” planetree with a large hole or ‘defect’, and figured it would break straight away from the four-ton winch.

Another 10” planetree had no visible ‘defects’, so we figured the trunk would hold strong, and that tree would uproot instead.

But the exact opposite happened!

We know next to nothing about tree biomechanics.”

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The issue with this scenario is if both these trees are in a homeowners yard. Say the homeowner is concerned for the safety of their kids and house. They are worried about the tree with the defect failing during a storm (where load dynamics are much different in effect than a straight winch pull) Would you, as a professional arborist, even attempt to suggest that the tree with the defect might be stronger than the apparent healthy tree? Probably not because the homeowner would laugh and go with another guys bid.

The orientation of the defect in relation to the load applied also makes a difference. Was the winch compressing the defect, pulling against its fibers, or laterally loading it? Wind loads are seldom straight on and will sway a tree's canopy in a figure eight pattern or pulse to pull and push a tree. The nature of a trees environment makes bio mechanics relatively unpredictable. We can test a hundred scenarios in controlled experiments and then as soon as we get in to the field, we are baffled by how we see trees react and deal with stresses.

Another issue is the fact that we cannot see the extent of internal decay that radiates from the visible defect. Has the decay made it to the root system? Its hard to tell. What we do know is that there is a defect in the structural part of the tree and the only safe tree is a removed tree. I'm not waving my saw saying cut em all down. If the tree with the defect is an open area..leave it be. Maybe take some weight off. But if it has a target to hit, short of guying it with a bunch of cables, removal is the only way to make it truly safe.

Dr. Gilman's statement of "we know next to nothing about tree bio mechanics" is spot on and I would wager that when we get to the point where we think we have a handle on the topic, trees will prove us misinformed.
 
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And the quote from 2010 Biomechanics Week. Dr. Ed Gilman: “We looked at one 10” planetree with a large hole or ‘defect’, and figured it would break straight away from the four-ton winch.

Another 10” planetree had no visible ‘defects’, so we figured the trunk would hold strong, and that tree would uproot instead.

But the exact opposite happened!

We know next to nothing about tree biomechanics.”

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Gilman's words no doubt are very accurate and are very damning when we are standing in a clients yard and they are asking us about the safety of their tree.

Great article though!
 
Phil, what this points out to us as professionals is an area requiring an improvement of our understanding and knowledge. This isn't a conclusive statement but one that tested our current approach to assessment. If this failed in a manner that was contrary to our assumptions then why? What are we not understanding about biomechanics. Herein lies an opportunity to further study and bring about more accurate conclusions. This will lead to better analyses and recommendation based on the research.

Those that undertake this can then clearly demonstrate that their recommendation is the best one vs. appealing to the fear factor.

As it stands now, fear trumps understanding because it can. With little to no protection for urban trees there tends to be an erring on the side of caution approach. People have a very limited idea of the value of their trees and thus see them only as a potential expense, i.e., no ROI.

We are still dealing with a lack of knowledge of the value of trees to human society. I recently delivered a brief seminar on the topic to a local shade tree commission which was reasonably attended. In many respects, while it was received well, it was preaching to the choir. But it is a first step.

We need to increase the recognition of the total value of trees, newly planted, mature and veteran, in the community of urban planners, developers, government and financiers. Then from there to the general public to create an informed clientele that will be looking for a more informed professional to advise them on their trees and urban canopy. Policies and practices can be put into place that will enable the protection of the urban canopy on both public and private lands with a better acceptance of such policies. There may even come a day when policies and regulations will be redundant! Yeah, wishful thinking.
 
The negative repercussions of media reports of a large tree crunching an innocent baby sleeping in her crib probably dooms many more trees than the isolated and rare incidents (50 deaths annually) cited in the article. Mr. and Mrs. Jones want their tree topped "to make it safer", or just removed altogether. They don't want to worry anymore about it killing them I don't blame them either.

I wonder what the economic cost over time to keep a large specimen alive and "safe" is over the course of several decades? Versus the cost of establishing not one, but a veritable grove of replacement trees. Does the dismally short average lifespan of a newly planted urban tree mean that "we" should be instead be spending that money on mature tree preservation? I don't think so.
 
The economic cost over time to keep a large specimen alive and "safe" is cheap. On average, maybe 2-4 hours of pruning every 5 years. Do the math, compared to r&r.

The cost of establishing not one, but a veritable grove of replacement trees, is high when you figure planting them *right*, watering, mulching etc. etc. This cost, and the dismally short average lifespan of a newly planted urban tree, plus the HUGE relative benefits from older trees, means that we should be spending more on mature tree preservation.

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Years ago my dad gave an estimate to an old lady to remove a medium/large honeylocust that was near the back corner of her house. He tried repeatedly to convince her that the tree was absolutely healthy and very strong. He didn't want to take it out, and offered alternatives.

She eventually got quite angry and yelled at him, "You don't have to sleep under it!" He politely agreed and we took out the tree. He later admitted that she had a point. Sometimes fear is irrational and it's pretty hard to un-scare someone.

Even with better understanding of biomechanics, we can never be certain. And without the assurance of 100% certainty, many customers will want the tree out. Not to mention that if you tell someone with certainty that a tree is absolutely safe, you have just potentially exposed yourself to liability when it crushes their house.

It's a tricky dance sometimes, and with no shortage of lawyers out there, better safe than sorry comes to mind. I mean, people are still more important than trees, right?
 
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I mean, people are still more important than trees, right?

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Depends which ones, Not many people benefit the environment at all let alone as much as trees, nor do they live on like a tree can, but we will take down trees that interfere with houses even though the tree was there long before the people came and cleared the site to build the house
 
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The economic cost over time to keep a large specimen alive and "safe" is cheap. On average, maybe 2-4 hours of pruning every 5 years. Do the math, compared to r&r.
smile.gif


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Thanks Guy. I had *assumed* that the monitoring and cost / time investment was more intensive, particularly for trees on municipal (as opposed to privately owned land). A 5 year pruning cycle seems generous re. due diligence.
On the main st. (Manitoba St.) downtown Bracebridge, Ontario is a public park with large silver maples planted along the street. The town has been gradually (over a period of a decade or more) planting new trees, and removing some of the old specimens. Given the presence of large limbs with large cavities hanging over vehicles and pedestrians, I think this is a prudent and sensible approach (as opposed to Huntsville, which plants white pines as street trees, and wraps them with burlap for the winter....but I digress)
 
I'm all for saving old trees and know their value.

The problem I see is that when a personal injury occurs because we, as Gilman says, "We know next to nothing about tree biomechanics.”

The the cost could be to our industry and our insurance the cost of preserving hundreds of trees. That has got to eat into the cost/benefit analysis a bit.
 
There is a whole raft of studies showing the real economic benefits of trees in the urban environment. Here's a link that will give you the highlights of the studies, http://www.actrees.org/files/Research/benefits_of_trees.pdf

NYC sees an annual $5.60 return on every $1 it spends on maintenance. Mature trees provide greater benefits and thus ROI then newly planted trees. It pays cities and towns to invest in their trees. Pittsburgh has developed an urban forest master plan (http://treepittsburgh.org/urban-forest-master-plan) to guide growth of the urban forest.

From 1995-2007 there were 407 deaths due to wind-related tree failures. That doesn't amount to much over 33/yr. To put it into perspective the numbers of fall deaths according to the Home Safety Council amounts to 6000/yr. Let's not even discuss the 33,00+/yr auto deaths. But I bet the old lady wouldn't think twice about getting into a car.

We have to work to improve our ability to tell a compelling story to our clients and with a confidence that will allay their fears. Then of course deliver the goods...
 
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The the cost could be to our industry and our insurance the cost of preserving hundreds of trees.

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Huh?

+1, th

The monitoring and cost / time investment is sometimes more intensive, particularly for long-neglected trees. No difference ime between municipal or privately owned land--all owners can forget. A 5 year pruning cycle is not that generous re. due diligence, for a slow-growing veteran, in tree time. :)

"On the main st. (Manitoba St.) downtown Bracebridge, Ontario is a public park with large silver maples planted along the street. The town has been gradually (over a period of a decade or more) planting new trees, and removing some of the old specimens. Given the presence of large limbs with large cavities hanging over vehicles and pedestrians, I think this is a prudent and sensible approach"

Did they attempt the often-prudenter and sensibler approach called reduction pruning? For maturing pecans and silver maples, 3 years apart is often plenty soon enough.
Cavities typically look worse than they are. Consider that they symbolize less mass and more flexibility.
Attached is an Very hollow Manitoba Maple in Ontario, sprawling over 2 houses, that was reduced in August, and escaped any ice damage. That's 'boxelder' to you southerners.
 
Our society still loves big trees. A real estate listing would feature the mature trees and it would sell quicker than a no tree yard. Even with what could be called hazardous kinda unattractive trees. No worries.

Development chewing up forest is the problem. That's why I may not be arborist material.
 
I think one of the keys to mature, sometimes damaged, tree preservation depends on who owns it and where it is. Places like cemeteries, golf courses, forest preserves, owners of large open land areas are way more prone to attempt a preservation project. Again, homeowners backyard, more than likely a removal. Every situation is different. I've refused to do topping jobs after politely explaining the reasons why I don't want to do it. Sometimes I get the wife convinced but not the husband...or the other way around. The only time I've refused a removal job is when I didn't have the equipment to get it done. I will always inform the owner of my professional assessment of the tree in question and provide a list of options. If they choose removal, then thats fine and I will offer to help with selection and planting of something new if they want it. I also think that the older folks get, the more likely they are to opt for a removal. The leaves, the randomly falling twigs and debris, storms, it all becomes too much of a headache.
 
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