RadioShack has a good selection of basic antenna mounting kits and mast to attach antennas to your roof, chimney, eves, vent pipes, or walls.
Here are some links to some tree mast mounts:
http://www.ronard.com/ BR http://www.ronard.com/tree.html BR http://www.ronard.com/tree_adjust.html BR
--MichaelCodanti BRBR Here's a good [http://www.student.math.uwaterloo.ca/~dajhorn/Projects/DIY%20Chimney%20Mast/ Do-It-Yourself Chimney mast]