Winter is a great time to see the architecture of trees and bushes without the leaves. When temps are above freezing as the ice and snow melts, look for crossing branches and dead, diseased, or damaged wood. Removing these will improve air and light circulation and may help to reduce damage from winds, storms and heavy snows. Trees pruned in early spring develop a callous around the cut much more rapidly than those pruned at other times.
10 Tips Before You Prune