This strange fibrous "thing" was found growing around the root of a leylandia. Initial hope was that it was a truffel and work could be abandoned! Any ideas what it is?

Blimey - and it's quite big too! I suppose it could be some kind of gall caused by a parasite - have you tried cutting into it? Also, could be it a man made object that the root had simply grown through over time? Very strange......

Unlikely to be a truffle - don't give up the day job yet!

Just an afterthought, but you could try sending it off to the RHS for 'official' indentification.

Is it actually solid ? Looks very much like a nest hornets wasps or certain bees ?

I think truffles are blacker?