You can hunt them from a tree...we do it up here continually in the Fall during deer season.

You can call to them from a tree. The key is to project your voice down and behind you, and call sparingly. Calling softely and sparingly, though, is often the combination that works the best in the Spring anyway, so the calling pattern doesn't really matter. You can also set a decoy 20 yards behind you. I've had gobbler flocks going nuts within 5 yards of my tree, and have oftentimes called in hen flocks of over 40 birds.

However...in the Spring there is just too much foliage for this to work, at least here in the Northeast. And as others have stated, it would drastically limit your options. Other than experience and woodsmanship, the next best skill in the turkey woods is knowing (or getting lucky more times than not!) when to move on a bird and when to sit tight. From a fixed position, you immediately remove yourself from probably 50% of most Spring turkey hunts...although, after you wait on a gobbler for 3 hours, move, and he then gobbles from your previous position not 20 minutes after you've left...[:@]...then maybe a fixed position might not be bad...[8D]