Tree Species Failure Profiles

JD3000 said:
And I would also like to see how specific trees are performing, or not, when afflicted with specific decay fungi and other maladies.
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good point JD3000. especially on a local basis. I'm not well read on this but I'm sure Guy knows the name of a few books

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I have a bunch too...

I want a resource that is species specific, shows common failure models, commonly occuring bugs n crud, and also shows how they react to many different decay fungi.

Biases aside, I think this would be a good resource.
 
treehumper said:
How would one account for past arboricultural practices and their impact on failure dynamics? In collecting species specific data what would the parameters be in selecting the specimens within the study group? Looking at urban trees in Toronto, especially the street or park trees, what do you know of the history of the work done on the trees and the impact it has on the particular species?

Maybe it would entail starting at a cellular level and working out from there. In so much as, the baseline would be the fundamental biomechanical strength with influencing factors layered on top in order to bolster or mitigate the end analysis of a given tree. In that way, one would be starting with factors that are consistent within a given species and then accounting for external factors that affect the final performance characteristics.
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sorry I don't quite follow the second paragraph if you can give example or other way of explaining. great points and questions in the first paragraph. I don't know all the history but it would be nice to know, especially going back to when they were small maturing trees. as for when they were older, it is evident that the silvers and Norway maples were 'managed' or not, with large cuts (6-20 inch) often on the main stem, made for the purpose of clearance or sunlight desires or house additions, which lead to high decay and risk resulting in removal or failure leading to removal.

interestingly, many of the 'topped' silver maples performed quite well in the ice 2013. especially where the topping was only half bad.

Had those stem cuts been made further out, even in particular to leave funny stubby limbs, at least the decay would not have caused decay and the coinciding risk associated. the decay at the end of a 6-20 foot stub would not cause risk, just awkward, not unnatural winter appearance. yes the stub may die back sometimes, but often not all the way back.

The point is, on many species, that stem cuts or removal cuts over 4 inch should often be traded for smaller reduction cuts further out, even if it doesn't look as good. remember that in 15 years that 8 inch cut at eye level will decay (especially on Maples) and get ugly and make a raccoon happy, while the further out (ideally 1.5-3" but at least less than 4") cut will be better looking, 15 years later, when you can't even see it. and make the birds happy.

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Ill take a stab at Rob's post. Start with how certain species form wood, first sap wood then ripe/heartwood. Look at how that species arranges vessels, tracheids, fibers, parenchyma etc and then probably cellulose, lignin, hemi-cellulose etc.

Then look at growth habit and how that tree responds to good/bad pruning, forces applied by weather events, open grown vs forest setting, etc etc.

Then perhaps look at how different fungi act on the tree both micro and macro.

About right?
 
I think a great example of how those variables come into play is seen with ash (specifically green and white). When they are healthy they really only commonly fail at a co-dominate - and quite easily at that. Otherwise, they are very strong. When they are sawn and dried, they are one of the stronger woods being preferred for baseball bats and shovel handles. However, when EAB kills them there is something else at play (I strongly suspect a decay fungus, but haven't seen anything identified...doesn't mean it hasn't been, just not last time I spent the energy to look!). Ambrosia beetle gets in there, so they may be vectoring something else? But anybody working with EAB killed trees knows they are not stable. Loggers won't take them because they split as soon as they go through the mill.

So the "ideal" Species failure profile for Fraxinus americana and F. pennsylvanica would discuss their strength when healthy. Their slightly higher than average likelihood of splitting at codominate branches, the probability that they will be killed by EAB and secondarily infested by ambrosia (not necessarily unique...), at which point they become excessively brittle (caused by ???) and may just as likely break off at the root ball or 15' up, but won't likely stand as a sturdy trunk for many years slowly shedding branches.
 
Good example but the imaginary resourcce would describe differences between the two mature species as well. Green tended to overextend many branches and sheer plane fracture was probably more common than failure of codoms at the juncture. Aggresive rot starting in the sapwood to borers is a great point and could also be mentioned when deacribing declining oak, birch, etc
 
JD3000 said:
I have a bunch too...

I want a resource that is species specific, shows common failure models, commonly occuring bugs n crud, and also shows how they react to many different decay fungi.

Biases aside, I think this would be a good resource.
Click to expand...
When your done with this how’s bout you pick up the pnw! I like what I hear and wish I could contribute, alas I’m just growing moss on my back, lichen in my arm pits, and algae on my (____)
 
treehumper said:
How would one account for past arboricultural practices and their impact on failure dynamics? In collecting species specific data what would the parameters be in selecting the specimens within the study group? Looking at urban trees in Toronto, especially the street or park trees, what do you know of the history of the work done on the trees and the impact it has on the particular species?

Maybe it would entail starting at a cellular level and working out from there. In so much as, the baseline would be the fundamental biomechanical strength with influencing factors layered on top in order to bolster or mitigate the end analysis of a given tree. In that way, one would be starting with factors that are consistent within a given species and then accounting for external factors that affect the final performance characteristics.
Click to expand...

Sounds easy, but ime utterly impossible to evade enough variables to produce useable results. Not to discourage anyone from trying though! And re fungi, do we really know they invariably lead to maladies?
 
EAB-related brittleness results from DRYING, not decay! We can't make sense of much if we are stuck in a decay-centric mindset. CODIT's D should be Damage, or Drying, but old habits die so hard!

Sad to see reputable publications stuck in that muck.
 
In some instances they will reduce wood strength but I'm not advocating mycophobia. Just examples, pictures, comparisons, etc
 
ATH said:
I think a great example of how those variables come into play is seen with ash (specifically green and white). When they are healthy they really only commonly fail at a co-dominate - and quite easily at that. Otherwise, they are very strong. When they are sawn and dried, they are one of the stronger woods being preferred for baseball bats and shovel handles. However, when EAB kills them there is something else at play (I strongly suspect a decay fungus, but haven't seen anything identified...doesn't mean it hasn't been, just not last time I spent the energy to look!). Ambrosia beetle gets in there, so they may be vectoring something else? But anybody working with EAB killed trees knows they are not stable. Loggers won't take them because they split as soon as they go through the mill.

So the "ideal" Species failure profile for Fraxinus americana and F. pennsylvanica would discuss their strength when healthy. Their slightly higher than average likelihood of splitting at codominate branches, the probability that they will be killed by EAB and secondarily infested by ambrosia (not necessarily unique...), at which point they become excessively brittle (caused by ???) and may just as likely break off at the root ball or 15' up, but won't likely stand as a sturdy trunk for many years slowly shedding branches.
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I think ash is still worth discussion, even though the population will likely be reduced to 1 percent. the remainder are therefore very important. that means that treated green ash survivors in particular are good candidates for winter reduction/thinning. so Yes I agree in the case of green ash. But white ash is similar in strength to the average species. and it's not that the green is weaker, it is more that it is over extended (as JD3000 said) and dense with end growth. To compound the problem, green ash is more spreading, while white ash is more upright. I use the term reduction/thinning because I believe it is often a good approach. especially for dense green ash. reduction or thinning alone is often not as good as a hybrid of the two. remember that proper thinning is not thinning out. it is thinning the outer portion (periphery). I like to think of reduction/reduction as 'thinning in'.

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guymayor said:
EAB-related brittleness results from DRYING, not decay! We can't make sense of much if we are stuck in a decay-centric mindset. CODIT's D should be Damage, or Drying, but old habits die so hard!

Sad to see reputable publications stuck in that muck.
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I have also seen sapwood FBs on dead dying ash too though. More often than not, they aren't there as you said.
 
Redtree said:
sorry I don't quite follow the second paragraph if you can give example or other way of explaining. great points and questions in the first paragraph.
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JD3000 said:
Ill take a stab at Rob's post. Start with how certain species form wood, first sap wood then ripe/heartwood. Look at how that species arranges vessels, tracheids, fibers, parenchyma etc and then probably cellulose, lignin, hemi-cellulose etc.

Then look at growth habit and how that tree responds to good/bad pruning, forces applied by weather events, open grown vs forest setting, etc etc.

Then perhaps look at how different fungi act on the tree both micro and macro.

About right?
Click to expand...

That's it! Known conditions that are consistent so meaningful comparisons can then be made. As long as there's a "yeah but" in there then we wouldn't have something useful to work with. The layers start with conditions at germination and initial establishment within the site, i.e., seeded or transplanted, site conditions/appropriateness of the site for the species, then all the rest of the factors that come into play effecting the trees properties.

As Guy said, The variables are possibly too many to allow for meaningful results beyond a gut feel.
 
guymayor said:
EAB-related brittleness results from DRYING, not decay! We can't make sense of much if we are stuck in a decay-centric mindset. CODIT's D should be Damage, or Drying, but old habits die so hard!

Sad to see reputable publications stuck in that muck.
Click to expand...
I haven't done the microscopic work to prove this...but based on anecdotal observations, I will disagree.

Having seen dead ash killed by other than EAB (over crowding, ash yellows, etc...) and stand in the woods without falling apart as it does after EAB it seems there is more going on.

Also, as mentioned ash lumber is very strong - whether air dried or kiln dried. Why is it so much weaker so quickly after EAB death? We do not see this immediate weakening after, for example, Oak Wilt. The other case were similar weakening is seen (but the breaks are a little different) would be DED-impacted Elm. Of course, we do know that a fungal pathogen (Armillaria) is almost always involved with these trees. How much of a role does that play in weakening the trees? I haven't seen much Armillaria in EAB-impacted ash.

Overarching point being: this is an easy example (well, maybe easy - at least to observe, maybe not explain). If I understand what Jason is proposing/asking for in a 'species failure profile' would be a description like this for each species. What are the common causes of failure, what factors influence those, can they me mitigated, more or less prone to failure than 'normal', etc...????
 
are you sure the wood is actually weaker after milling? I'd bet there's a chance the lumbermen are just paranoid or playing it safe. I would actually say that the wood isn't necessarily more brittle, I would say it is more rigid, due to drying. it can't be bent as far. it is less flexible. when you fell a HEALTHY ash it certainly smashes to pieces more than a sugar Maple. Then a dead one is even worse. they don't use it for bats any longer as much as they use maple. it's weak to begin with. the bug leaves the bark so loose that when you fell it, it smashes even more, compared to one dead from another cause. have your rake ready.

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Yes...EAB killed Ash is weaker lumber. I have experienced it first hand and have visited several sawmills to see it happening.

The mass switch to maple bats is relatively recent... McGuire/Sossa era. Ash is still used and is still very strong. Still preferred wood of tool handles for centuries - not because they didn't know better but because they have tried everything else as well and nothing was better.
 
infected ash may be weaker than ash that isn't but don't you agree that Sugar Maple (hard Maple) is stronger than Ash?

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