Posted: 16/04/2015 at 14:16
If it has been there and fruiting for 25 years it's hard to think of something in the soil that would kill it unless something has changed, other than honeyfungus - have you lost any other trees/shrubs?
Just a thought, but from your photo it looks to be planted very close to the fence - plants positioned close to a fence notoriously suffer from drought as fences and walls create a 'rain shadow' - coupled with this we had a very long very dry spell last year. Could your tree have suffered from drought last year? Did you give it plenty of water through the dry spell?
If it was affected by drought, that could have weakened the tree and allowed some sort of infection to strike.