Progression of Fistulina hepatica in oak

[agg221]

I'd welcome some thoughts on this one.

 

I was having a look at a milling job a couple of weeks back - in a wood. The wood has not been managed for a fair while and there are some oaks at just over 30" dbh which are getting near to harvesting as the owner doesn't want to lose the understorey completely.

 

I spotted one oak of this size which had a fair number of brackets of what I think were Fistulina, very low down on the buttresses. They were well past their best but the shape and colour looked right.

 

This is interesting, as I have a need for some decent brown oak in the long term but it doesn't really matter when I get it, any time in the next 5yrs would be OK. The tree does not need to come out right now for any other reasons. It is well in to the fenced wood, a long way from public access, and although it would not be ideal if it fell the wrong way, it would not be disastrous in any direction. In an ideal world we would now wait until the colour has run through the tree so far as possible, balancing progression of colour up the trunk against progression of excessive structural decay at the base and pick an optimum time to fell. So the questions are:

 

How to tell when the colour has gone well through the tree

Are there external signs to use in assessing when it has gone too far at the base and it isn't a good idea to wait any longer?

Anyone have a sense of the timeframe for progression of each of these in trying to pick the optimum time to fell?

 

Any thoughts welcome.

 

Cheers

 

Alec

[woody paul]

Interesting question should be some good answers come in or not.

[Gary Prentice]

I think you're going to struggle to get answers for this.

 

The only method I can think of would involve resistograph or picus testing, neither of which, I imagine, would be easy to interpret for colour itself.

 

Look forward to some answers too.

[Kveldssanger]

Referring to Fungal Decomposition of Wood (page 337-8), the decay of this fungus is very slow to progress in the heartwood of oak, to the degree that discolouration / staining preceeds wood degradation by potentially a long time. Anecdotally, it's one oft seen on areas of oak where heartwood is exposed (even if only a tiny fragment is exposed and allows for the creation of a fruiting body atop a sort of false stem), and one rarely associated with failure (though of course it can - eventually). If the oak is not particularly old, then it may simply be a case of an extra five years being no extra 'issue' and the wood won't have begun to deteriorate through brown and soft rot of Fistulina.

 

As for staining, unless you track with radial cores there is little hope of discerning, and radial cores would discolour / damage the wood undesirably.

[OakStag]

Heavy crown forms are common during late stages of decay, just an idea to look for however failure only tends to occur on multistemmed limbs and crowns such as quercus pollards hope this helps.

 

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[Gary Prentice]

Heavy crown forms are common during late stages of decay, just an idea to look for however failure only tends to occur on multistemmed limbs and crowns such as quercus pollards hope this helps.

 

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Sorry, what do you mean by 'heavy crown forms'?

[OakStag]

dense crown forms so epicormic growth.

 

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[Kveldssanger]

For a heart rot such as Fistulina, the vascular efficacy of the oak shouldn't be compromised and thus this observation about epicormics might not apply. The rot (if you can even call it that for long periods of time, as the mycelium gets its carbon fron the tannins) is restricted to the heartwood, which is - in the conductivity sense - almost useless.

[OakStag]

oh right sorry my bad I just read about it in a book let me think... This book http://www.treesource.co.uk/principles-of-tree-hazard-assessment-and-management.-2013-edition.~3775

 

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[Kveldssanger]

In which case you may very well have a point. That jogs my memory - I was told last weekend that Fistulina can cause basal burring on oak. In that sense, activation of epicormic buds at the base of the host oak could perhaps occur.