| brassbaboon |
You can definitely sculpt the tree trunk and branches with Sculpey, I've done that. But the preferred means of making the tree trunk and branches is to use lots of thin wire twisted together. There's a Youtube video of a guy making trees that way. Basically you take a clump of wire about half as thick as a pencil, then you twist it together for a half inch or so, then separate that into two clumps, and twist them, then separate those into four clumps and twist them, etc. until you run out of wire. Then you can paint or glue or spread epoxy putty on them to hold them and glue clumps of flocking to it. Makes great trees. I've made a couple that way too.
You can also find small twigs out in the yard and use them, although they can be a bit fragile.