I often include a referemce to the local Cooperative Extension System when answering questions about forests and trees. They are local experts trained to help with horticultural and garden questions and know what works in a given area. They also have the best information on local chemical regulations and product vendors.

Gardening guide, Marie Iannotti, has written a very good introduction to The Cooperative Extension System. She covers the purpose and mission of the CES and provides a link to a map that will help you find you local state Extension professional.