Bryce 5 Tree-lab trees use less polys and are waaay more detailed, unless you want any kind of non-symmetrical trunk, of course! I would use something like what the (above) posted for you closer trunks, and then Treelab trees if you have Bryce 5, for the Midground fillers, and then 2D alpha "pict" trees for the background. Remember that if you run out of cool trees, you can alpha-channel your own Bryce 5 trees all in Bryce, and re-import them into a scene as 2D pict object trees for your backgrounds... That cuts the PCPT (poly-count-per-tree, do you like that or WHAT?!??!) down to : ONE!