Q: A few years ago this totally healthy oak was struck very hard by another falling tree. Eventually a wound developed. I decided to cut it down for safety of my home. However as you can see in the pictures, there was a ring inside the tree of a gelatinous material as well as a white spongy material. Was this a disease? or from the injury?

A: The falling tree bruised the bark and caused it to fall off. Eventually, rainwater entered the wound and began the inevitable process of fungal invasion. The spongy stuff is part of the fungal mass which is feeding on the trunk interior, causing it to be hollow.

You were right to take it down.