Really??? I didn't know that. I thought when you build over the trees, they go back to tree credit. This must be fixed. I know now to bulldoze before I build then.
How do you verify this is happening?
You can see it happening if you build a road through trees then bulldoze the road, all the same trees re-appear.
Now this doesn't verify that they are still counted, mod tools plugin on the workshop may help with that, but I have also seen the same behaviour in the asset editor and this does have a count.
Two trees, as per counter on chirpy's banner...
Build a path over one of them...
Still two trees.
Remove the path and the tree is still there.