@ Fred: I appreciate the info.
When you say, difficult to get rid of, do you you mean difficult to cut down, or difficult to keep from coming back?
To this I say both. They are a multi-trunked species. The trunks of fully grown trees are between 4"-8" in diameter. The branches however are the issue. They tangle amongst themselves and nearby trees making a very dense web of branches. Another problem is that the roots must be destroyed to prevent the tree from regrowing.
Regarding clearing whatever brush, it is hard to beat someone from a part of the world where they use machetes. You won't believe how fast they can clear it.
The branches are cut easily with a machete if they are still green and fresh, however when the tree has gone through it's life cycle, (they seem to be an edge species.) the dry branches are very tough and a machete just seems to bounce off.
Goats are a possibility, if they will eat the stuff, especially if they like the bark. Not sure about pigs.
True, however I'm not sure if they would be edible since these trees are poisonous and in the same family as poison oak, ivy and sumac. I don't think I'm even allowed to burn the dead trees because I've heard the smoke is a toxic irritant.
@ K: That's definitely a good point. I guess that's one way to turn a problem into a solution
Here is a video I sent in to Paul and the rest of the admin. at Permies. This will give you an idea of what I'm trying to deal with.