This was built on a rolling platform, about 4 by 6 feet. The main body of the tree grew up from an oversized stump . The extra width in the stump provided a seat for the Cat to drape herself about, and looked like the remains of one branch of the original trunk. The remaining trunk rose nearly 15 feet, to bare, evil-looking branches spreading 10 to 12 feet wide.
Construction was pure, "throw some more dark on it" stagecraft: A small bench made a form for the seating are of the stump, and the main trunk and a core for each branch were 2 x 2 lumber, stuck together with 4" deck screws and a few strategically-placed 1 x 4 braces. They stapled chicken wire onto the armature, forming the body and branches, and the skirt of the stump.
Over the chicken wire went a skin made of newspapers soaked in diluted (off-) white carpenter's glue. When dry, this made a shell, usually less than 1/16 inche thick, but quite hard. Sounded a lot like plastic... Lots of brown and black paints later, and we had a quite realistic looking tree.
After the play, we asked to salvage it, rather than see it scrapped on the spot. We had to slice off three long branches, just to get it out of the auditorium, then I rode home with it in the back of a pickup. When Halloween approached, we put the branches back in an approximation of their original positions, leaving gaping wounds where the skin and chicken wire had been cut through. A few newspapers and a quart or so of glue, and the "grafts" were in place. I touched it up with a couple different brown housepaints, followed by black, gray, and green spray can "airbrushes".
In the dark, it looks great; in the sun, well, it's a prop! I think the best testimonial the tree received was a woodpecker working on it several times this Fall!
Click on the thumbnails below, for a (little) better view. I may try in brighter light, maybe I can get some better images...