You can contact your local county Extension office. The Dane County Tree board is affiliated with the Dane County Extension Office and tree care information is available through Lisa Johnson, the Dane County UW-Extension Horticulture Educator.
For further information, the International Society of Arboriculture has an informative website that covers the following topics:
What does my tree need and why?
What do I need to know before buying and planting?
What tree hazards and treatments should I know about?