Winter is a great time of year to prune trees because disease causing/carrying insects that would normally be attracted to tree wounds are dormant. Follow the link to learn more…
Pruning branches creates open wounds on a tree. The open wounds produce chemicals that attract insects that either carry diseases with them or may be capable of damaging the tree themselves: Dutch Elm Disease, Oak Wilt, Emerald Ash Borer, etc. Problem insects are generally dormant during the winter, making it an ideal time to prune most trees species.