Certified Tree Risk Assessor
- Thread starter Mike Cantolina
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I think we all need to ask ourselves: is tree risk assessment just a "best guess" of the trees health? Ive seen what are obviously bad trees make it through harsh climate conditions over what appear to be healthy trees, if the BMP`s will have the standard incorporated into it.....then it is just a matter of an already "CERTIFIED" or Non Certified individual to follow such!
It is not a matter of "trees stand up before they fall down" mentality, its a matter of when do we mitigate the risks involved (above or below), I imagine out east they`re not too worried about assessments...........nature threw more out than what could be handled, truth be told you can use the stair statistics, lightning stats or the lotto to try & bring in a rationale scenario.......but, what if this winter one of those trees on the hillside falls on the house? even if that doesnt happen............the growth rates will continue to "weight" the trees in the direction of the house (target).................from an insurance point of view & an Inspectors point of view the question would be................how could this accident have been prevented???? & what if the trees were trimmed & still fell...........then the question will be a little more in depth (liability?)
Now the bigger question: Do we really need a Certification to determine a trees risks?
LXT.................
It is not a matter of "trees stand up before they fall down" mentality, its a matter of when do we mitigate the risks involved (above or below), I imagine out east they`re not too worried about assessments...........nature threw more out than what could be handled, truth be told you can use the stair statistics, lightning stats or the lotto to try & bring in a rationale scenario.......but, what if this winter one of those trees on the hillside falls on the house? even if that doesnt happen............the growth rates will continue to "weight" the trees in the direction of the house (target).................from an insurance point of view & an Inspectors point of view the question would be................how could this accident have been prevented???? & what if the trees were trimmed & still fell...........then the question will be a little more in depth (liability?)
Now the bigger question: Do we really need a Certification to determine a trees risks?
LXT.................
treeclimber101
UNCLE BUCK
ncredible thread and posts. I brought up the subject of Zevr's post to TRACE instructor BCMA Terry Flanagan a couple of weeks ago and he was a bit caught by surprise and unaware. So much of this subject has researchers scurrying around as we type I bet. Very interesting times.
Wulky's stuff, as usual.... very thought provoking. I just read Ansi A300 part 9 (2011) (Tree Risk/Structure Assessment) last night and was searching for this very kind of thread for those as interested as I am in this topic.
At the seminar the entity of Tree Failure Data Base was invoked in discussion but not elaborated on. Wonder just how much input (shell wall thickness thresholds, species specific reaction wood/ woundwood competence, lean, species specific pathogens, etc. etc.) that findings of this data base has on where we are headed in....
....the evolution of the standard on quantifying the risk of trees that is currently in vogue....and at the end of the day, the report generated to protect targets (or at least give fore warning) from catastrophic events with our new knowledge/system. Seems to me it is way underused as mentioned above, while some look to carve their names in stone in history.
Hard to fathom but as I brought this subject up on another forum many of the resident meat heads were dramatically offended that someone other than them with the knowledge of the ages as td artiste s (read (cough while saying) "bbbulllschit"), and are armed and ready to fight any suggestion that they attend a seminar or crack a book or that anyone could be allowed to trump their unsystematic and unscientific opinion. lol.
He's talking about you , ya know lol sounds like a poet and here he is a caveman go figure
Corymbia
ArboristSite Operative
Jeff, you are right in saying I didn't use common sense and I accept that "common sense" is not common and is often flawed.
In making my comments I used reason and statistics something that is absent in many so called risk assessments in the tree industry. By example, if we have a tree that has a hollow of say 75% of its radius that has formed slowly over the last few decades is this a defect? Yes! Is there an increased likelihood of failure? Perhaps not! If we look at Mattheck's graph we will see a number of trees that failed with 85% decay or more and these were once trees with 75% decay and obviously the transition to 85% decay or greater doesn't happen overnight.
Because trees are continually self-optimising the rate of new growth and the rate of decay are both important factors in considering the significance of the t/R ratio. Other factors that are important are the height of the tree, the geometry of the tree, the surface area of the tree, the exposure of the tree, structures adjacent to the tree and so on.
Let us just assume that the tree with this defect is 10 times more likely to fail than the average tree, does that make this tree hazardous? Yes but this tree may not be hazardous enough to result in a risk that requires any action. What we need to know is “what is the risk from this tree?” We have identified a hazard and a hazard with an increased likelihood of failure but now we need to know how likely it is to cause a particular consequence. (Most risk calculations concerning people consider the risk of death).
So the question that we need to answer is how likely is this tree to fall when there is a person underneath who is likely to be hit and killed by the tree. It stands to reason that the risk of harm from trees in general is low with the annual risk of mortality from trees in most western countries being between 1 in 5,000,000 and 1 in 10,000,000 (in Australia it is approximately 1 in 8,000,000) it woul seem that the average tree poses a very small level of risk (UK figures suggest 1 in 10,000,000 for "trees in or adjacent to high public use").
If our particular tree, as a result of the defect, is 10 times more likely to fail than an average tree but is otherwise average it would have a 1 in 1,000,000 chance of killing someone. If resolving the problem with the tree is going to cost say $2,000 the question is doing this a prudent and reasonable use of resources? To save a single life from being killed by a tree like this would require $2,000 X 1,000,000 (the risk of the tree killing someone). This is a cost per life saved of $2,000,000,000. Is this reasonable or could this money been better spent elsewhere (like cancer research or traffic lights)?
Yet, we as arborists often are out there saying this tree is hazardous, and is a "high risk". Yes compared with other trees it is a higher risk. Unfortunately the word "High" is relative and is in essence meaningless unless we can compare this risk in quantitative terms. Sure dealing with the tree may be a good paying job but it would be completely unnecessary and does nothing but serve to perpetuate the myth that trees are more dangerous than they actually are.
In my opinion, risk assessment without some form of probabilistic outcome is akin to having an election without a vote ... you get an outcome that is dependant solely on the perspective of the person that makes the decision, the decision may or may not be representative of any reality outside of that persons perspective, and the outcome is often used to validate the accuracy of the perspective.
There you go again. You paint with such a broad brush that it makes me wonder about your ethic's.
Jeff
Jeff
Corymbia
ArboristSite Operative
Thank goodness for that!
They do however behave with enough consistency that textbooks have been written on some of the most minute details about them. As with many things in arboriculture, there are many generalised rules with exceptions that seem to mock us.
Corymbia
ArboristSite Operative
Good point. Because the building is stationay it cant move so it may get hit ( I am forever amazed at how many times trees missing the building or fail slowly and just rest gently on the roof.
When it comes to property damage we can probably be more objective. If the tree were to fail, how much damage on average would it cause. Let's say that a tree like this in this situation will on average cause $10,000 worth of damage and let’s say that the tree has a 1 in 1,000 chance of failing in the following year (if there were 1,000 identical trees 1 would fail in the following year). That means, on average, the tree will cause $10 worth of damage in the next year.
In that situation what do you think would be sensible to spend avoiding an annual risk of $10? How about over the next 25 years? Perhaps $250. If it is going to cost $500 to remove the tree you would be better of investing the money or paying it off the mortgage
Now you may be inclined to remove the tree for other reasons but spending $500 to remove a $10 a year loss is just plain dumb unless you are only paying 2% interest on your mortgage.
Corymbia
ArboristSite Operative
Good point. Because the building is stationary it can’t move so it may get hit ( I am forever amazed at how many times trees missing the building or fail slowly and just rest gently on the roof.
When it comes to property damage we can probably be more objective. If the tree were to fail, how much damage on average would it cause. Let's say that a tree like this in this situation will on average cause $10,000 worth of damage and let’s say that the tree has a 1 in 1,000 chance of failing in the following year (if there were 1,000 identical trees 1 would fail in the following year). That means, on average, the tree will cause $10 worth of damage in the next year.
In that situation what do you think would be sensible to spend avoiding an annual risk of $10? How about over the next 25 years? Perhaps $250. If it is going to cost $500 to remove the tree you would be better of investing the money or paying it off the mortgage
Now you may be inclined to remove the tree for other reasons but spending $500 to remove a $10 a year loss is just plain dumb unless you are only paying 2% interest on your mortgage.
Corymbia
ArboristSite Operative
Would you like to explain ... Are you suggesting that trees can read?:msp_unsure:
ozzy42
Addicted to ArboristSite
You bring up a good point as far as the actual amount of damage actually done when trees fail.
People always want to remove the trees closest to the house when in reality it's the one a distance away that cause greater damage.Trees and limbs close to the house tend to [as you say] ''rest gently on the roof.''
Sorry but i disagree with you on this one.You used one form of math on the amount of damage to spread the risk:$10,000 down to $10.
But then compare the $500 to remove the risk to $10
No HO that I know have is going to have 1000 trees that may cause $10,000 damage to their home.
$500 compaired to the possibilty of $10,000 damage to one's largest single investment[their home] buys a lot of piece of mind.
Telling a HO that you can think of it as a $10 per year risk ain't going to cut it.
Pelorus
Uva uvam vivendo varia fit
"I believe the ability to accurately questimate the hazard that some trees present is being highly over estimated."
I very much enjoyed learning about rigging/vector forces from articles written the late Dr. Peter Donzelli, a name familiar to all here.
I very much enjoyed learning about rigging/vector forces from articles written the late Dr. Peter Donzelli, a name familiar to all here.
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Corymbia
ArboristSite Operative
You miss the point. There is only one tree so this tree on average will do $10 worth of damage a year. Spending $500 to remove the small risk of damage makes little sense. I can invest $500 at 4% and make $20 a year. Better to spend money on insurance which they should realy do in any case and which will cover the damage caused by the tree and give far greater peace of mind since it covers many other issues such as fire, flood, wind damage, hail damage and so on.
I am not sure what it is like in the US but in Australia pointing out that tree damage is only a minor risk to the insurer (so low they are not interested in the trees or their condition) and yet they are insuring their house for a few hundred a year should help them understand how low the risk is from tree damage.
The fact that we find it hard to educate our clients shouldn’t be reason for us not to do our job properly or to provide our clients with accurate information. It is up to our clients to accept or ignore our advice it is, not our right to feed them crap because it is easier.
Im thinking you have missed the point Corymbia, your figures work on paper..........but as with most things regarding nature, they just dont add up in the real world!!!
Ya see what is stated above is how it works over here in most instances, here....if my tree falls through your house, act of God & your insurance will foot the bill............so now lets focus on the reality of what was mentioned above!!!!
LXT.............
Corymbia
ArboristSite Operative
I am not sure how observable, quantified risk is anything but "real world". However I do take your point that some questions need to be answered and in particular the question you have raised.
from an insurance point of view & an Inspectors point of view the question would be................how could this accident have been prevented???? & what if the trees were trimmed & still fell...........then the question will be a little more in depth (liability?)
The question that is likely to be asked is not what could be done to prevent the accident but rather was there any reasonably practicable solution available? We are not called to do anything or everything to reduce risk but rather that which is reasonably practicable. In this instance it could be easily argued that there wasn't a reasonably practicable solution since the cost of remedying the problem was disproportionate to the potential harm.
Let’s get real world. So the tree has a lean but a severe storm comes through and blows a different tree down instead ... something we have all seen. Should we remove all trees? Obviously not! But don't all trees pose an element of risk? Sure they do but that risk is usually so small that we accept or ignore it particularly when we weigh the risk against the benefit we get from trees and the cost of cure.
Many, if not most tree failures, occur during inclement weather. If parts with defects fail in the same condition that non-defective parts fail this is generally considered to indicate that these defects are no weaker than the non-defective tree parts that fail. If we can’t determine which non-defective parts will fail during inclement weather, then it may be appropriate not to be so concerned about many defects that fail during the same conditions. Something to think about!
Perhaps I am a little odd but when I was pruning trees we use to guarantee our work against storm damage for the following 12 months after we pruned them, regardless of how severe the storm. The idea was suggested to me by a company that was doing it in the US. It took them a little time to convince me of the wisdom that trees seldom fail if they are not pruned and pruning further reduced the likelihood of failure. In the 15 years and having pruned over 15,000 trees we had one broken branch to repair.
Apparently you have never done Line Clearance work, I have gone through & trimmed entire circuits only to have a storm come through & find myself back there on an outage re-trimming/removing & the same can be said for the residential field as well, how many trees do you think failed out East that had some form of maintenance done on them prior to the storm?
Many good points..........But none that are showing the need for a Certified position!!!
LXT................
Corymbia
ArboristSite Operative
I agree, the is no NEED for a certified position but there is certainly a NEED for good training and a sound understanding of some potentially complex matters. Certification does not necessarily resolve all or any of the issues associated with risk assessment. For some certification will be about making a grab for work. For others it will be about doing as little as possible and hoping for a return, for others still it will be a part of an ongoing process to bring about excellence not just in themselves but also in their profession.
Certification does, however, offer a number of advantages. It ensures that those who are certified have at least been exposed to relevant information and training and it allows the public to be aware that they have been exposed to and hopefully benefited from the same. It also allows for some overall unified approach and concepts. It does not ensure that a risk assessment is carried out correctly or that an accurate and consistent appraisal of risk will be given ... that is up to the arborist concerned who, like you and I, are fallible and have their.
No system is perfect but that does not mean that we do not progress towards perfection and encourage and support those that take steps in that direction. If as a result I need to spend a few dollars each year and spend a few hours getting better educated so be it. I am not going to put any effort into resisting either of those, rather I would prefer to put my effort into improving my income and the income of my colleagues and at increasing my expertise and knowledge levels along with the increasing the knowledge of those whom I come into contact, colleagues and customers alike.
Sounds like a plan.
If there is a concern about the amount of blood those money grubbers will be draining out of the struggling men and women out there, let's compare it to the BCMA. Cost to test is $450; that's $150/year, $12.50/month, 41 cents a day for the first 3 years. Not that painful, compared to other costs of doing business.
Renewal is $250/ 3 years, $83.33/year, ~$7/month, 23 cents a day. I have chronic anemia from leukemia, but don't notice that amount of blood pouring out from the wounds gouged by those cert-pushing money grubbers. :msp_rolleyes: I just renewed for the second time, because it does not cost, it PAYS, in the form of no-bid work, at higher rates, for starters. Certs have worked for me since 1992.
The CEU's required cost nothing or little, if you're somewhat enterprising about it. I just paid a couple hundred to get a fi####l at expo, and had a blast doing it, but you can stay in your town year around and get em in any number of ways. It seems reasonable to show you're learning something once in a while and staying somewhat current with the art and science and business of tree care.
Compare it to safety and gear--should we be happy with what we learned 20-30 years ago?
LXT, since you are doing fine without it, what is there to complain about? Are you on a crusade to save tree guys 23 cents a day? :msp_w00t:
kinda funny the auto-editor here cut out #### from fi####l...
ozzy's pic following must figure in this...somewhere...looks like that tree mighta been topped...? re $10/day, depends on your deductible...
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ozzy42
Addicted to ArboristSite
Here is some of that 10$ pr yr damage.
