Investigating and assessing root decay

[Treecreeper1961]

Some fungi species such as Meripilus giganteus and Kretzmaria deusta decay roots leading to serious implications, as we all know. Can anyone help me understand more about assessing the risks of such infections?

 

1. How do arbs. go about examining roots suspected of being decayed?

 

2. Does anyone have practical experience of this that they can share?

 

3. Is it realistic to excavate around roots to look for decay?

 

4. Is there anything such as the tR ratio that is used to assess integrity of roots with decay?

 

Thanks in advance for any input.

[Paul Barton]

I have used an air-spade to investigate tree roots on trees affected by M.giganteus. I am informed that it degrades the underside of roots first so it is important to excavate right under roots to check.

 

I have heard it recommended that using a fluorence testing machine on the foliage combined with a detailed VTA assessment is the first step before excavations - but I don't have a fluorimeter so I go straight for the air-spade!

[David Humphries]

Air spade here also.

 

Although I don't think it entirely necessary to uncover the whole diameter of the roots, as once partially uncovered I've found that you can use a hammer to sound for decay.

 

 

 

.

[Fungus]

Some fungi species such as Meripilus giganteus and Kretzschmaria deusta decay roots leading to serious implications ... examining roots suspected of being decayed ? Is it realistic to excavate around roots to look for decay?

 

First - if possible - you'll have to identify the pathogen, to be sure of what type of woodrot you're looking for in/on the roots and in the buttresses and/or trunk base :

- white rot (Heterobasidion annosum, Pholiota squarrosa, Grifola frondosa, Armillaria species, Xerula radicata, Abortiporus biennis, etc. or Inonotus dryadeus and M. giganteus combined with soft rot of living tissue),

- white rot with selective delignification (Ganoderma species),

- soft rot (K. deusta, M. giganteus and Inonotus dryadeus in living tissue) or

- brown rot (Fistulina hepatica, Phaeolus schweinitzii, Sparassis crispa, etc.).

And with airspading alone, one can't assess woodrot inside the tree roots or buttresses.

[Paul Barton]

How do you go about assessing internal rot of roots Gerrit?

[Tony Croft aka hamadryad]

The primary concern when investigating meripilus is certainly the pressence or lack of "shear killers" that is to say roots that go down at angles from the major surface roots helping dissipate shear forces placed on tension roots. meripilus tends to generate a wide and very shallow root base, more so than beech is known for and hence the windthrow issues.

 

As for Kretz, if youve identified it, its probably well advanced and time to get out the resist-o-graph

[Treecreeper1961]

How do you go about assessing internal rot of roots Gerrit?

I second that question Gerrit.

Although, I assume 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.

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.

[Treecreeper1961]

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

[Treecreeper1961]

The primary concern when investigating meripilus is certainly the pressence or lack of "shear killers" that is to say roots that go down at angles from the major surface roots helping dissipate shear forces placed on tension roots. meripilus tends to generate a wide and very shallow root base, more so than beech is known for and hence the windthrow issues.

 

As for Kretz, if youve identified it, its probably well advanced and time to get out the resist-o-graph

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?

[Treecreeper1961]

First - if possible - you'll have to identify the pathogen, to be sure of what type of woodrot you're looking for in/on the roots and in the buttresses and/or trunk base :

- white rot (Heterobasidion annosum, Pholiota squarrosa, Grifola frondosa, Armillaria species, Xerula radicata, Abortiporus biennis, etc. or Inonotus dryadeus and M. giganteus combined with soft rot of living tissue),

- white rot with selective delignification (Ganoderma species),

- soft rot (K. deusta, M. giganteus and Inonotus dryadeus in living tissue) or

- brown rot (Fistulina hepatica, Phaeolus schweinitzii, Sparassis crispa, etc.).

And with airspading alone, one can't assess woodrot inside the tree roots or buttresses.

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?