Been trying to find a tutorial without much success, so I'll have to start yet another thread here instead

I'm going to make a forest with pretty big trees. What's important is that the trunks should be really big so that my character can hide behind them. I've been trying to paint some pine trees and tweaking the paintfx settings, but I can't really seem to get my desired effect. Also, the pine trees take billions of polys, I'd be fine using something less detailed.