On 26/11/2013 08:40, echinosum wrote:

'Jeff Layman[_2_ Wrote:
;995725']On 25/11/2013 11:25, echinosum wrote:
-
The splits in the trunk are vertical.-

That's interesting. I would have thought that vertical splits were the

results of compression damage.

Aren't the classic splits that oaks and the like suffer from fungus,
resulting in them becoming hollow trees, vertical splits. What do you
mean compression damage - driving a vehicle into it? If it was bent
over by the wind to cause local compression, that would be horizontal
rather than vertical surely.

I get lots of little vertical splits in some of my fruit trees, but they
heal. I think this is due to intermittent drought and water-plenty, so
when it grows fast the outer parts of the tree can't keep up and split.
But those are much smaller than this. The bark is still partly intact
over the splits in this case.

Time for a bit of clarification, methinks. Are we both talking about
the same thing? I was assuming structural cracks that at the very least
are through the bark and into the sapwood - maybe even into heartwood.

By compression damage I mean that caused by pushing down from the crown.
Normally, one would expect a tree subject to extreme winds to be
either uprooted or snapped off at its weakest point. A horizontal crack
would appear at that point, gradually extending inwards until it had
weakened the heartwood sufficiently for the tree to break off. That
would be as a result of exceeding the tensile strength of the remaining
wood at that position. Consider, though, that wood is much stronger
across the grain than along it. It is far easier to cut wood by
splitting it along the grain than across it, for example. There is a
very interesting discussion of tree structure and strength at
http://www.nhm.ac.uk/nature-online/l...rees/session3/

If a wind-rocked tree has good roots and high-tensile strength wood, it
isn't going to get uprooted or snapped. But that doesn't necessarily
mean that it will withstand compression, to the same degree. Also, as
you note, fungal damage might play a part. I found this at
http://www.arborilogical.com/service...-and-bracing/:
"Trees with trunks that have narrow angles of branch attachments may
develop vertical splits. Such cracks are often a result of structural
stress or storm damage. When such splits are found, immediate attention
is needed to prevent complete failure. Your arborist can advise you as
to whether the tree should be removed or if cabling and bracing is a
viable alternative".

--

Jeff