Spring is the appropriate time to prune most trees, but not oak trees. When oak trees are pruned in the spring the fresh sap that the wounds secret attracts beatles. The beatles can infect the oak trees with the oak-wilt disease. Red oaks, pin oaks, and black oaks may die quickly after they are infected with the oak-wilt fungus. Other oaks may live longer but they too will eventually die. So prune your oaks in the winter when they are totally dormant.

How to prune trees is another issue that we get frequent questions about. While browsing the INTERNET on the subject of pruning I came across a very well written and informative article on pruning, along with some great diagrams that illustrate where cuts should be made. Here is the website from the University of Missouri: http://extension.missouri.edu/xplor/agguides/hort/g06870.htm