Sounds like you’ve got the

Sounds like you've got the freedom of a narrative video, and displacement may be your friend here. Shooting the same patch of trees from different angles can all look like the same forest. If you have any running scenes, you may have actors run in a circle around a smooth panning camera. These are both ways to maximize your background.

Perhaps your options include getting stock video of a more fitting forest, and letting that establish your setting, then you shoot where your favorite trees are.

What kind of scenes are you working on? How closely do the actors need to interact with this endless forest?

-Jackson