Here’s a tutorial on making trees from scouring pads.. They’re very nice looking, and it looks like a fun project, but frankly you can get nice pre-made trees from a variety of sources. Still, they’re bound to be a lot cheaper, and if you’re a do-it-yourselfer ….
trees
Making Sagebrush Trees
Ryan Scow has a tutorial on making miniature wargames trees from sage brush. They are very good looking.
Making Acacia Trees
WarFactory has a tutorial on making African Acacia Trees.
Modeling Trees
Here’s some advice on modeling trees from air conditioning filters.
Spooky Trees and Fog Machine
Ironhands has some evil trees he built from kids toys, and a page explaining how he used an electric fog machine to add some great effects to his tabletop games.
Now how about some fog through the spooky trees.