If you need weed tufts here is a cheap way to make them.

If you want to make your own pine trees ask and I can walk you through
how to make some pretty nice looking ones (4-9") using galvanized wire,
masking tape, wisk broom bristles, chopped up hemp rope, fine ground
foam, some paint (trunk color mainly), and aquanet to hold it togehter.
Tools - vise grips/pilers, cordless drill with a hook in the chuck,
wire cutters

You can see pics of the trees and the latest from my build on facebook,
or http://community.webshots.com/user/timothysysop look under the model
railroad album.