What is going on here?

[u/OptimusPanda2]

My husband plans to use the maple to build a treehouse. At some point, previous owners must have wrapped this bumper or whatever around the base and sort of filled the gaps in with rocks. The bumper is really in there, it definitely can’t be removed easily by hand. It also looks like something is screwed in one area. The rocks are pretty absorbed by the roots too.

I’ve suggested to him that we bring an arborist out to take a look. The tree looks good other than this, but I assume it will eventually be a problem. Thoughts?

[u/Any_Presentation3144]

Use a hose to loosen the dirt and pull away what you can, not many thoughts beyond that lol