Interesting Biomechanics

[David Humphries]

tidy wee inosculated branch on sycamore......

 

 

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[David Humphries]

rather impressive beech base......

 

 

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[daltontrees]

Seen last week. Anyone know what has caused these lumpy shelves on this Ash?

[David Humphries]

Seen last week. Anyone know what has caused these lumpy shelves on this Ash?

 

Good shot Jules.

 

this is something I've seen on a few tree species.

 

The most prominant I can recall is this holm oak in the stumpery at Ickworth in Suffolk.

 

my reading of the mechanics would be that these 'shelves' are perhaps reaction wood around fibre kinking on the compression side of trees that have white rot, much like that associated with Inonotus dryadeus in the tree below.

 

maybe your ash has decay issues associated with Ganoderma, Perreniporia or Inonotus?

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[daltontrees]

David, thank you for replying, I was a bit despondent that there was no reply to this, as I hate to allow something new-ish to pass without building my knowledge.

 

I have seen it in lesser form elsewhere, including in Edinburgh last week, but never where it has been so pronounced and multiple. My thought at the time was along the lines of yours but without association with white rot (although that now makes sense), I thought it was associated with rotational shear forces at points of weakness. Since the shelves don't go all the way round, it seems inevitable that the forces must resolve themselves by localised buckling. And hence the adaptive growth.

 

The tree in question was almost 30m tall, a good 8m higher than the rest of the group, and it was on the top of a steep embankment on the edge of fields and very exposed. Higher up was a large tear wound where a compression fork with included bark and extensive decay come off a few years (I am guessing) previously. Dessicated Inonotus hispidus fruiting bodies were found on the ground nearby, with no other likely hosts than this Ash. I thought I could see old attachment points around the tear wound.

 

It all adds up to exceptional torsion on the crown and stem, which has been partly removed by the loss of the codominant stem at the compression fork. The I.d could have been active in the stem beforehand.

 

Does all this make sense, including the ability of I.h to cause white rot proximally 2-3 m from point of infection?

[David Humphries]

................Does all this make sense, including the ability of I.h to cause white rot proximally 2-3 m from point of infection?

 

We've found I. hispidus decay will extend into wood volumes significant distance (above & below) from where it fruits, although I haven't had the opportunity to disect whole trunks that have had hispidus (only) association.

 

 

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[Kveldssanger]

^

 

Indeed. Mattheck and Weber suggest white rot causes such incidents of 'sagging' or 'shelving' in the trunk in Manual of Wood Decays in Trees, as the tree looks to build sounder wood around the softening area.

 

Bulging can also be exacerbated by internal cavities caused by rot, which leads to similar repair features.

 

(reply to bottom post on the prior page)

[Kveldssanger]

Saw this the other weekend on an old lapsed ash stool with multiple stems. Who said elephants were only found in zoos?

 

[daltontrees]

^

 

Indeed. Mattheck and Weber suggest white rot causes such incidents of 'sagging' or 'shelving' in the trunk in Manual of Wood Decays in Trees, as the tree looks to build sounder wood around the softening area.

 

Bulging can also be exacerbated by internal cavities caused by rot, which leads to similar repair features.

 

(reply to bottom post on the prior page)

 

I fell asleep last night trying to find this is book, will look again.

[daltontrees]

We've found I. hispidus decay will extend into wood volumes significant distance (above & below) from where it fruits, although I haven't had the opportunity to disect whole trunks that have had hispidus (only) association.

 

 

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Many thanks again, the pictures make the point very well. I.h is I believe capable of early soft rot, which I generally associate with less aerobic conditions which would be found in downward acting decay