I am reasonably confident about this identification and it's certainly the closest in appearance to the many bracket fungi with the possible exception of Ganderm adspersum. It is supposed to be quite hard to tell these apart. This fungus is living on an ash tree which we had felled last year. The tree had been infected with this parasitic fungus and we were advised that it could well be eating the heartwood of the live tree. There was an ominous hollow sound if you struck the trunk near the fungus and since the tree could well have fallen on the house it had to come down. Fortunately it was also in the interest of the electricity company to have it felled as it could also have brought down the power lines going up the lane. They therefore organised and paid for the felling of the tree. By counting the rings, not all of which were clear, the tree was at least 195 years old but the strangest thing happened during the felling.

The branches, which were as large as some trees, were to be cut up for a local farmer to use. When the contractors started to do this they blunted their chain saws.  Close examination found that the inside of these branches was hollow and had a mixture of ivy roots, sand and at least one large stone which had caused the damage. It was an piece of igneous rock, none of which is to be found locally. How did it get inside a branch which for most of its life was more than 3 metres off the ground even in the year 1900?

Nobody has yet suggested a sensible explanation.

On Fraxinus excelsior overlooking the road outside our house, 30th September 2004

Added on September 30th 2004, modified 1st October 2004, January 26th 2005, updated 19th Nov 2014