Liability and Decay

[guymayor]

This comes up a lot so here's an example of parts of a report. Tree was topped xx years before.

ASSIGNMENT

Determine whether tree failure was reasonably foreseeable.


FACTORS IMPACTING TREE FAILURE … 20xx

1. Wind speeds of mph were recorded at …at the local airport (Appendix A), with gusts of … mph. They came from … degrees, so the wind was funneled between … and …, increasing the force that impacted the subject tree.
2. Stem-girdling root. A large root from another tree wrapped around (girdled) the base of the failed tree. After I pulled it out, the deep groove indicated that circulation had been choked off. Stem-girdling roots dam the flow of resources, with significant effects on tree health and structure. (Tate, Watson, Johnson, Hauer, Meilleur)
3. Overextended branches. The tree had not been pruned since it was last reduced so its branches had been reaching for the sun and the sky for that period of time.
4. High vitality, and time of year. and …, the neighbor, both corroborated what the pictures show: the tree was full of healthy green leaves, with no visible problems. A lot of water is pulled up into the leaves, adding to the load.
5. Lean. The tree grew away from ... I roughly measured the lean in the trunk from above the ground to … above the ground at … degrees, and the corresponding lean in the comparable tree at …degrees. “Leans of 40%+ are high risk” (USFS). On both trees, the lean ‘self-corrects’., as the growth above the leaning section turns toward the vertical. “Self-correcting trees are unlikely to fail…” (Matheny & Clark)
6. Decay. Fruiting bodies of the wood decay fungus hypoxylon, Kretzschmaeria deusta,are evident on the trunk and branches of the failed tree. “The inconspicuous fruiting structures are easy to overlook and many arborists may not recognize (hypoxylon) as a butt rot fungus.” (Luley) “…symptoms do not become evident in the crown for a long time. This means that even apparently healthy trees with a full crown may break unexpectedly in strong winds.” (Schwarze)

Despite the growth of decay in the …years since the failure, a rope attached to the broken tip held my 176 pounds of weight. I bounced and pulled on it, but it did not break. Decay is often compartmentalized (Shigo), and is seldom the primary factor in tree failures.


STANDARD OF CARE: UTILITIES AND MUNICIPALITIES AND RESIDENTS

The comparable tree at …is regularly pruned by the local utility to clear the 15’ easement around the wires to the north. The City of policy on privately owned trees is to refer citizens to sources of information, and reliable contractors. (Appendix D). The City has no record of notification from citizens regarding the failed tree. The policies and actions of the utility and the City are reasonable and typical for this region.

Residents in… can be held responsible for tree failures if they are notified by certified mail of an imminent danger, and fail to act on that notice within 30 days. reported they never received any comments regarding the safety of this tree.



CONCLUSIONS

Based on available evidence, I conclude

1. The failure may not have been reasonably foreseeable to an arborist trained to assess tree risk.
2. The failure was not reasonably foreseeable by anyone who is not trained to assess tree risk.

REFERENCES

Luley, C. Wood Decay Fungi 2005

Matheny, N. and Clark, J. Evaluation of Hazard Trees in Urban Areas (2nd ed.) 1994

Meilleur, G. http://www.historictreecare.com/wp-...LBG-III-Managing-Stem-Girdling-Roots1.doc.pdf 2009

Schwarze, F.W.M.R. Fungal Strategies of Wood Decay in Trees 2000

Shigo, A. CODIT: The Compartmentalization of Wood Decay in Trees 1977 http://www.nrs.fs.fed.us/pubs/misc/ne_aib405.pdf

USFS Urban Tree Risk Management Guide 2003: http://www.na.fs.fed.us/spfo/pubs/uf/utrmm/

 

[nuthin_special]

Thanks for this contribution Guy,

1. The failure may not have been reasonably foreseeable to an arborist trained to assess tree risk.

Thats some ambiguity there in the conclusion, makes me wonder what the point is of even completing a report if this is the result.

I've wondered if in my reports I should be including clear references to source material as you have here.

V

 

[treehumper]

Um, yeah. that's a conclusion as it should be stated, Simple and to the point as set out.

 

[Leroy]

Good stuff. Thanks for posting Guy.

 

[ward]

Thanks for this contribution Guy,

1. The failure may not have been reasonably foreseeable to an arborist trained to assess tree risk.

Thats some ambiguity there in the conclusion, makes me wonder what the point is of even completing a report if this is the result.

I've wondered if in my reports I should be including clear references to source material as you have here.

V

"Assignment: Determine if the tree failure was reasonably foreseen"

I suspect this is to ascertain whether liability is to be assigned to the property owner whose tree it was or whether it was for the homeowner who suffered damages. It seems a little odd that property owners trees which fail onto others may be released from liability if they failed due to "Acts of God" (i.e. no human knower could have reasonably foreseen the failure). I'm pretty sure Guy had meant only to conclude that no reasonably qualified expert could have known with certainty that the tree would fail, and not necessarily to have proven that "Acts of God" had occured. I don't think Guy is a theologian.

 

[guymayor]

V, the ambiguity exists, unavoidable. The problem got solved to the extent possible. Likely is what matters; defendable absolutes are very rare. And it does not pay to say anything undefendable.
References are good to know and use and list, but they can be overdone. Page numbers are good to mark, and take the stack to court for testimony (in the rare case that a case goes to trial).

Theologian haha. 6 natural factors listed; judge for yourself which are divine, if that matters. some say all nature is divine, and God proves her own acts without any help! Atheism may not be easily defendable; I wouldn't go there, but that's just me.

Yes, ime 'Was it reasonably foreseeable' is a common question when trees hit people or property, and other people are blamed. 'foreseen' would be a different scope; like reading tea leaves?

 

[ward]

Reasonably foreseeable=could have reasonably be foreseen. Equivalent concept, separate locution I think.

Reasonably foreseeable is not the same as 'reasonably foreseen'. That would be akin to possessing a crystal ball.

 

[familytreeman]

Cool post! thank you for showing us that. hearing from you on this topic a few times , i see how we have the trees defending us. In an imperfect world, there will almost alwys be these contributing factors

 

[benfuest]

Stem-girdling root. A large root from another tree wrapped around (girdled) the base of the failed tree. After I pulled it out, the deep groove indicated that circulation had been choked off. Stem-girdling roots dam the flow of resources, with significant effects on tree health and structure. (Tate, Watson, Johnson, Hauer, Meilleur)

Managing Stem Girdling Roots, Mayor 2009, page 3, para 4.
"Roots that circle the trunk instead of growing away from the trunk injure the tree by reducing transport of water, minerals and sugars where the root presses against the trunk. The injury increases with time, often leading to tree decline.

Ok so you have established the failed tree had girdling root that had been in place long enough to inflict a "deep grove" and "dam the flow of resources" Your point 3 describes a tree with branches "reaching for the sun and sky". Post reduction. In point 4 you describe a tree in "High vitality" "full of healthy green leaves" You also say "A lot of water is pulled up into the leaves adding to the load"

• Overextended branches. The tree had not been pruned since it was last reduced so its branches had been reaching for the sun and the sky for that period of time.

• High vitality, and time of year. and …, the neighbor, both corroborated what the pictures show: the tree was full of healthy green leaves, with no visible problems. A lot of water is pulled up into the leaves, adding to the load.

I suspect a hard core legal eagle would press you on the contradictions with a view to calling into question your expertise and therefore the validity of your report. Unless of course you could satisfactory field the questions re the contradictions

 

[guymayor]

Thanks fam, ward...Was there a qwuestion in there, Ben?
The way I learned botany, water is pulled up through the xylem, the inner tree, and used in the leaves as food is made. Then, the food's sent down in the sapwood, the outer tree. Girdling roots dam that pathway, preventing metabolism and storage. So, a tree can have high vitality in the outer tree and lots of green leaves, yet fail due to dysfunction and decay.
Lots of books you can consult on that. Thanks for checking in!

 

[benfuest]

"was there a question in there, Ben"
Yes lots of them, but your response requires clarification first.
"The way I learnt botany, water is pulled up through the xylem, the inner tree, and used in the leaves as food is made. Then, the food's sent down in the sapwood, the outer tree" This is incorrect.

Xylem or primary xylem does indeed carry water and minerals up the tree, there are 3 or 4 forces that come to play to facilitate this movement. As the tree grows and produces more cells, new xylem vessels are produced, secondary xylem. The primary xylem vessels empty and become what we refer to as sapwood and then eventually heartwood.

Outside of the xylem layer is the Cambium layer and then the Phloem vessel layer. These phloem vessels are responsible for the transportation of nutrients down the tree. Not the sapwood.

Outside of the phloem layer is the bark.

There will inevitably be exceptions, but in the context of your explanation of the function of xylem/sapwood, I think not.

 

[ward]

I was in a situation last year where I had to establish whether there was any indication that a fir which fell onto my client could have been noticed prior to its failure. For me, the standard of basic tree risk assessment does not include anything beyond vta. (X-ray vision is not the standard). The failure was due in this case to an insufficiently robust rootplate (a single root on the side) that eventually gave way under the duress of a storm. It would have been an exceptionally astute arborist to pull away the ivy and deduce what was there based on vta of the buttress roots. I now know the telltale sign of this kind of rootplate and make it a part of my tree risk assessment.
Interesting because in your case you are establishing that "The failure may not have been reasonably foreseeable to an arborist trained to assess tree risk."
You are not claiming that no trained arborist could have reasonably foreseen the failure, only that some would not have seen it as failure prone. While it may be hard to ascertain the exact species of decay conk on the stems, it seems that their mere presence should have raised red flags and, in conjunction with the knowledge that it had been previously topped, most skilled arborists would be willing to assign at least some heightened probability of failure to the stem. Missing that in a visual tree assessment seems to me possibly worse than mere 'difference of opinion', but a failure to get it right (simpliciter). If not professionally negligent, isn't it still some form of incompetence which would separate those who saw the tree as (at least potentially) hazardous due to its defects and those who did not. While a homeowner could not be expected to provide that level of analysis, aren't these features standard defects listed on any tree risk assessment report form?

 

[guymayor]

Thanks Ben, sugar flows down the phloem, which transitions into sapwood (which also conducts nutrients) and xylem. Nitpicks aside, does the rest of it look similar to what you see in the UK then?

Ward, good post; helped me see a major omission—timespan. Was failure foreseeable in the next day, or the next century? Big difference; shoulda been set out from the start.

VTA should definitely include pulling away ivy and finding the flare; not much astuteness needed there, just the willingness to get the hands dirty, good on you to make the move. Amazing that others don’t; they might as well be watching the tree on tv.

‘Advanced’ assessment means that tools or expertise on site is lacking, so a return vi$it is needed. Best to have all we need the first time.
If you saw rootplate structure was lacking, and knew it failed during a storm, that’s 3 factors, including crown load.
Was rootplate issue from decay, obstructions, girdling… no Rx without an RCX, gotta look closer to mitigate, or perhaps even to get an idea of how major that factor was.

For me, some digging is part of vta. Borrow the client’s shovel if needed; no delays on that.
A conk on the stem is a yellow flag that could turn green or red. Many fungi stay on the bark, and many woodrotters are not aggressive, and/or sealed off. Still something to examine more of course.
If previous topping cuts can be reached with a ladder, assessing that area is part of vta too.

What’s it mean if a condition is noted on tree risk assessment report forms, that depends. Ticking off boxes is not assessing.
Compartmentalization can be key, turning ‘defects’ or points of stress into points of strength, but it’s not mentioned on the TRAQ form.

To say a condition or a tree is ‘potentially hazardous’ is not saying much--aren't they all?
Better to have timeframe (duh) and be more specific.
Did your client survive? Did they collect on a claim?

 

[benfuest]

I cant comment what others do in the UK but for me personally your report lacks detail.

What was the tree species ?
How tall was it?
What diameter?
How deep was the groove?
To what extent in % the girdled root on the stem?
Define local airport ? (my local airport is 30 miles away)
"Branches reaching for the sun and the sky" gives the impression the tree was in competition. Was it?
High vitality/ full of healthy green leaves. could this have been a panic response?

Despite the growth of decay in the …years since the failure, a rope attached to the broken tip held my 176 pounds of weight. I bounced and pulled on it, but it did not break. Decay is often compartmentalized (Shigo), and is seldom the primary factor in tree failures.

Tree Failure, implies the whole tree fell over. Or was it a branch that came off?
The broken tip that held your 176 pounds implies it was a branch that came off and you tied into the remains?
for me the only thing the report tells me is how much you weigh.
....years since the failure. Why would any one commision a report re foreseeable years after the event?

 

[guymayor]

Ben it's quite common to commission a report re foreseeable years after the event. That's when responsibility/liability for the event gets sorted; see title of thread. Detail left out to anonymize and share the gist. Some answers below; sorry but table didn't paste. Ta!


East tree (failed)

West tree (intact)

Circumference at breast height (cbh)

84”

79”

Distance from road

21’

17’

Height where lean begins

5’ 9” (lower failure point)

5’ 7”

Angle of lean

27.2 degrees

24.8 degrees

Height where lean self-corrects toward vertical

16’ 4” (upper failure point)

17’ 3”

Abutting a slower-growing red maple

Yes

Yes

Hypoxylon fungus viewable from ground

Yes

Yes

Dead branches visible

Yes

Yes

Cavity visible

Yes

Yes

Height

?

60’- 4”

Size of girdling root at base

2”+

None

Soil Erosion/Compaction

Yes

No

Diameter at the break of previously broken branch

5.7”

None

 

[benfuest]

How long is the statute of limitation in such cases?
Surely in such cases the gathering of evidence , data and pictures is an imperative. Best done before the clean up team arrives.
Failure to commission a report till years after the event would raise more than an eyebrow. Presumably it is the responsibility of the claimant and team to prove negligence.
Are you working for the claimant or the defendant and was your report commissioned by the home owner or the legal representatives ?
I suspect if you posted this over here, however discrete, the a posing side would move to have your report removed but not before handing it over pre disclosure to there own expert to dismantle. Making you vulnerable to litigation from your client for disclosing before time required.

 

[guymayor]

Thanks Ben, limits are 3 years for some things and 7 for others, dismantling was attempted, case is closed, moving on. If I hear of a case where copper failed I'll let you know. Lots of folks are watching, but none yet.