Investigating and assessing root decay

[David Humphries]

David,

Thanks for the pics.

What were the indications that led to the investigation of these trees? Fruiting bodies? Arising above the roots or on the buttresses?

What was the conclusion of investigations?

Paul's mention of VTA prompted me to pick up The Body Language Of Trees. I had forgotten there is a mention of root decay there. Mattheck suggests that 50 to 70% of mechanically functioning roots must be sound.

He also refers to Rr or the static root plate radius. This has jogged my memory a bit. Most uprooted windblown trees I have looked at have lifted a root plate with a very consistent radius. Quite often the roots also have a distinctive blackening or blueing decay pattern.

For some reason I have assumed root decay generally starts at the extremes of roots and progresses towards the center of the root plate. Is this a fair assumption?

How much labour is involved in the work your pictures show?

How do you reinstate the root zone?

 

Thanks, Ben

 

There have been fruiting bodies of Meripilus giganteus over a couple of years.

The Beech in the shot above is not within one of our high target zones but I have the compressor & airspade at hand so felt compelled to have a closer look, inpart further investigation & and also ongoing study.

 

Spent an hour using the spade & then after assessment, back filled the rhizone with the original soil & topped up with local excavated soil horizon.

 

The tree is staying for now, no perceivable canopy issues associated with root dysfunction. Will monitor & reassess over the next two/three years.

 

 

Root decay can begin at the extremities or directly underneath where the old tap root was, depends on fungal species & particular MO.

 

 

 

.

[Tony Croft aka hamadryad]

Gerrit,

I have recently found a large ash with a mass of Pholiota squarrosa bodies on the north side of the base. The wood here appears to be sound for the moment. On the south side there is extensive white rot, so soft that I can push my hand in and tear out fists full of spongy pulp. There are no fruiting bodies on the south side. There is, however, remnants of bootlaces there. Considering the succession of decay organisms, would Armillaria sp. precede or succeed P. squarrosa?

 

what species is the tree? P squarosus will be there first, stress and armillaria sp secondary

[Tony Croft aka hamadryad]

Hamadryad,

Apologies for the earlier misspelling!

What you are saying is that the morphology of roots is or can be determined by the presence of M. giganteus?

 

root morphology-

 

We have the shear root ball= the quantity of soil that is required to counter balance the entire tree if we was to pull it out of the ground roots and all the soil would balance the crown with an imaginary finger at the hotspot on the stem the wrist of the stem, between flare/butresses and the main stem diameter (where a life belt forms after stem buckles resulting from a high wind.

 

It is the shear killers on roots past the shear ball that stop this soil ball rotating and failing through both soil and root shearing forces. If the roots in the lower half of the ball are rotted they no longer work and the root plate must adapt to a wider shallower form, till eventualy as with sitka spruce we have a flat root plate that can be thrown like a coat stand

[Treecreeper1961]

what species is the tree? P squarosus will be there first, stress and armillaria sp secondary

 

The tree is Fraxinus excelsior. Requires some climbing work before felling. Adjacent trees for life line, still, can't wait.

[Tony Croft aka hamadryad]

photo the base for us creeper

[Treecreeper1961]

photo the base for us creeper

O.k. Before I post these photos, sorry for the picture quality, I thought my camera was average but my daughters is not great. Also, when I said I had recently found a mass of P. squarrosa it was actually a couple of months ago and they don't look so fresh now!

As far as the bootlaces go, perhaps that was my imagination or I may have

mistaken the black zone line for bootlaces, not sure.

 

All in all, I was not that impressed with my recollection of it when I went back today.Sorry,

 

Never the less, there is some pretty impressive decay of the roots and buttresses going on and perhaps two different types of decay, with a white rot lower down and what seems like a more brittle rot extending further up the stem. Maybe the harder decayed wood is early selective de-lignification?

 

Not he best offering I am afraid but Santa may be bringing me a replacement camera.

[Fungus]

Considering the succession of decay organisms, would Armillaria sp. precede or succeed P. squarrosa?

 

Ben,

Precede, co-incide and/or succeed on living trees, but always with distinct mycelial territories. And after the tree has died, necrotrophic parasitic Armillaria species always follow the biotrophic parasitic P. squarrosa.

Edited November 21, 2011 by Fungus

[Fungus]

1. As far as the bootlaces go, perhaps that was my imagination or I may have mistaken the black zone line for bootlaces

2. Maybe the harder decayed wood is early selective de-lignification?

 

1. The black layer could also be melanine plaques of Armillaria.

2. Is there any proof of the presence of Ganoderma species then ?

 

And could the clusters of red "drops" in the last photo be Nectria peziza ?

[Fungus]

1. it is done as you would do when assessing stem decay, sounding (as David is demonstrating), drilling (as Hamayadrad is suggesting) or with the more sophisticated sonic and thermal imagery.

2. The thought has just occurred to me,however, is the confirmation of decay in significant structural roots sufficient to form prognosis without delving further into extensive testing? Obviously the size and number of roots makes it a different equation to solve than when considering remaining integrity of stems that are decayed.

 

Ben & Paul,

1. Yes, in that order, where I find the resistograph to be the most precise instrument.

2. That depends on the specific circumstances (risk management) and on the conditions (stability) of the trunk, the buttresses and the roots.

[Treecreeper1961]

1. The black layer could also be melanine plaques of Armillaria.

2. Is there any proof of the presence of Ganoderma species then ?

 

And could the clusters of red "drops" in the last photo be Nectria peziza ?

 

1.That's interesting. What do these melanine plaques represent, in theory? When I identified the fruiting bodies on the less decayed side I was confident they were P.squarrosa by remnants of scales and after dissecting the stalk. Perhaps I was wrong or perhaps they are both present. Will I have to wait another year to find out? The tree will be down by then.

 

2.No, I have not seen any evidence of Ganoderma. Why do you ask?

 

3.I was wondering if anyone would pick up on the little red fruits. N. peziza. Thats new to me.

 

Thanks very much for your thoughts.