On 11/06/16 18:48, Nick Maclaren wrote:
In article ,
Spider wrote:

As to ivy killing trees, it tends only to happen when the mature ivy
(with larger leaves) is growing in the crown of the tree. In wet and
windy weather, the extra windage on the large leaves is enough to cause
the tree to topple, especially when coupled with saturated soil.

It does that only when the tree is growing very slowly - no way
can ivy keep up with a healthy silver birch! I believe that it
can grow completely round a tree and strangle it, but I have never
seen that - it's extremely rare if it happens.

Ivy behaving like a "strangler fig", eh? Can't say I've ever seen it
happening, either. It seems to me that ivy tends to grow up rather than
round (strangler figs grow down /and/ round, of course). I have a few
trees, mainly conifers, which have been taken over by ivy - one in
particular has a lot more ivy leaves than conifer leaves! But I'll have
a look later to see if there are any encircling growths, rather than
well-spaced "spiral" growths, which I would perhaps expect, and which
would not strangle the tree they are growing on.

The main problem with ivy on conifers is that they disfigure them; once
the tree's lower growth has been smothered, it never grows back, and
even higher up the tree eventually looks like it has the arboreal
equivalent of mange!

I think the OP's finding of ivy under the bark was coincidental to the
bark already being damaged by some pathogen. Ivy will happily find its
way into any gap - roof tiles being a favourite. There is a galvanised
steel coal bunker here, and I was amazed to find ivy growing /inside/
it. It had found its way in through a tiny gap in an overlapping corner
seam at the bottom of the bunker, and was growing up to reach the light
allowed in by the ill-fitting cover.

--

Jeff

In article ,
Jeff Layman wrote:

Ivy behaving like a "strangler fig", eh? Can't say I've ever seen it
happening, either. It seems to me that ivy tends to grow up rather than
round (strangler figs grow down /and/ round, of course).

Right. I have seen ivy fork and rejoin, like a strangler fig, but
never enough to form a complete circuit. I have seen it distort
the growth of a tree, so I deduce that strangling a tree is (in
theory) possible a few times in a million.

I think the OP's finding of ivy under the bark was coincidental to the
bark already being damaged by some pathogen. Ivy will happily find its
way into any gap - roof tiles being a favourite. ...

Absolutely. If he could provide serious evidence of his hypothesis,
it would be publishable in an academic journal as a phenomenon new to
science.


Regards,
Nick Maclaren.