No problem man. When it comes to trees and environmental objects/terrain, you can get away with a lot with LOD models, you could have it set up so that the tree may be 10 polys at a distance but as it gets closer to the character it gets more detailed. Same with the terrain, if you do the terrain in blocks instead of one huge object, you could have LODs on distant terrain, which would achieve the same effect.

If you're able to use normal maps in the engine you're using this would also open up a whole new bag of tricks, although it would take longer to make you could get great results out of a very low poly house (for example) with a normal map, compared to a higher poly house without one