You can pick up a rubber gas mask for cheap at any military surplus store, or ebay has them. Ours was only like, 15 bucks. All you have to do is remove the filter and filter chamber. They work like a charm!!!
As far as smoking out of a tree? I dunno about that. It seems like as soon as you drilled the hole the first few hits would taste like bark. Not to mention all the "scoobie snacks" you would be sucking in...... To each his own though!!!

~ChillSmoker:stoned: