This doesn't look right...

[kutto]

Any ideas? I know it affects birch trees, palm trees, and the Wright boulder.

[Simsample]

I would guess... either some borked custom content, or a corrupt objects package file. Maybe one of the objects packages in basegame 3D folder.

[Sagana]

In this thread:
Problems with trees and crashing game

down the page aways, someone else had this exact problem. I think the solution there ended up being a base game reinstall, but it doesn't look like the OP ever said if that fixed it for sure or not.