Tree stump becomes amazing wicking hugel fungi thing

Two years ago I cut down a tree. Fungi soon colonised the stump and most of it’s now as soft as cardboard. I started hollowing it out with my fingers(!) and look how deep it’s rotten away! Here’s what amazes me about it:

1. We have drought each summer and soil always dries out. But no matter how long I water this baby the water never rises to the surface.
2. This means all that water’s going deep underground somewhere. The plum trees planted right next to the stump must be sucking up that moisture. It’s become an inground natural wicking system!
3. The wood keeps rotting and fungi keeps growing. It’s adding nutrients to the water and creating new soil out of the trunk.

I’m now wondering whether to turn it into a simultaneous compost pit by throwing in stuff and letting it rot away, leaching nutrients into the water. But it’s permanently moist inside and I don’t want to create potentially bad bacteria by anaerobic decomposition, so not sure whether I should just leave it alone. Thought?

Looks like a great place to dump some wood chips and assorted compostable materials. Keep a good thing going.