Westonbirt reported on Facebook that they cut down their champion Betula ermanii × pubescens because a large branch fell off and there was considerable decay in its trunk. They went on to explain that "This tree was affected by Ganoderma applanatum, a common bracket fungus that causes rot in the heartwood of a variety of trees." I thought the rot came first and the Ganoderma opportunistically moved in. Or is that only half the story, and once it moves in, it finishes off the rot, or it moves the rot into the heartwood? Or am I confusing this story with some other fungus?