I was wondering what the easiest way to make or get a fair number of 3D trees would be? They don't have to be to perfect scale, just something that I can scatter on the board to show cover & concealment, etc.

Thanks.

Are you just after easiest, or easiest and cheapest?

If you're only after easiest, probably the best I can suggest is to check your local model railroading store (Hobbytown is one possible name to look for).  You should be able to pick up a big bag of trees from them for a reasonable price and be ready to go.

Two words:  Woodland Scenics.  They sell their stuff in every train store.  They have a great selection, they're easy to assemble (sometimes no assembly), and they look great on the table.  I've used their trees in wargaming for years.  Heres the URL:  www.woodlandscenics.com

Look through the tabs at the top of the page under Landscaping.  

If you need trees in a hurry, go to your local discount store and buy a bag or bucket of plastic dinosaurs or farm animals from the toy section. They usually contain a handfull of plastic trees and rocks. If you have the time, slap on some paint and glue them to a carboard base to make them stand up better.
I find that having a handfull of these available during a game can really help to detail an encounter or a battlefield.

[Deleted by moderator; sorry, no linking to competing paper terrain/model sites. D]