I have the same brush you have also in centtex. I'll tell you what I do and you can go from there.
1. mesquite-never ever shread. Go to brushbusters and follow the guidlines or look up killing mesquite here.
2. ceder/winged elm-basil stem spray of 5% remedy and diesel per gallon. Has worked well for me.
3. youpon- mine come out very easily with the
fel. I can take a clumps of 2"ers out easily. They are very shallow rooted. A chain works on most to close the the trees to use a
fel.
Take it slow and don't try to do it all at once. Hope it helps.