I have seen and admired the larger Bonsai's for some time now
and would like to have at least one in my collection.

Every year I go out to my Dad's ranch and get about 3 elms that the
cattle beat up. I start looking now and remove them just before spring.
The problem is, they are only around 1 inch in diameter at the base
and I would like them to be much larger ( several inches at the base).
There are bigger Yaupon's and Elm's, but their lowest branch is 1 ft
or more from the ground.

I don't know if I should air layer ( would be hard to keep watered) these
big trees
or start cutting them way back to encourage lower branches.

Could I get some advise?
Is there a good book on just this subject?

BTW, I live in Texas and have not had any Bonsai's die on me for a few
years now (collected included).

Thanks
Steve