Someone mentioned management of a group of trees by phone recently.

http://www.treedictionary.com/DICT2003/SOUND/

There are some very well written articles here that might apply. Especially
"Managing Cavity Trees for Wildlife in the Northeast"

http://www.treedictionary.com/DICT2003/hardtoget/

Something to think about.
--
Sincerely,
John A. Keslick, Jr.
Consulting Arborist
http://home.ccil.org/~treeman
and www.treedictionary.com
Beware of so-called tree experts who do not understand tree biology.
Storms, fires, floods, earthquakes, and volcanic eruptions keep reminding us
that we are not the boss.