Another wild and crazy idea for you all!
From what we've seen in the game, from the trailers and videos, is all metal building voxels and terrain voxels. All the rocks and trees, while detailed, appear to be "elements", which can't be mined. I'm proposing that trees and bushes, while not necessarily made from voxels themselves, generate or release materials that can be made into wood voxels. Especially if there are a variety of types of wood colors and grains.
Why? Because nothing says luxury like an all wood interior!
Hmm... that wasn't wild or crazy...