Odd willow stem...

[sloth]

As above, strange stem form on salix at Colchester zoo. It's almost like its grown against something long since removed, causing a flat, circular depression in the stem, with 'ears'. But it hasn't. Not right for a target canker either, no necrosis. Looks fairly normal when viewed from the other side.

Apologies for poor quality phone pics and finger blur! So, any suggestions?

[HCR]

Stereum rugosum?

[sloth]

Maybe, although I'd expect to see fruit bodies by the time symptoms are so pronounced. Also (I didn't get up close, the wife finds me embarrassing enough as it is ) Butin says it only forms the canker on Quercus. I think the bark in the centre of the depression was still alive as well. I have a gold card so will be there again some point, will have a closer look

[HCR]

Interested to hear what a more detailed inspection discloses

[sloth]

A prod and probe and plenty of photos I'll try and remember to take a proper camera too...

[Giles Hill]

It could just be adaptive growth following a partial stem failure caused by mechanical or other physical damage.

[sloth]

Could be looking at the pics, though in the flesh that didn't seem right?