When it comes to dying, diseased, or weakened branches there really is not a bad time to have them removed from the tree. But in general, the best time to prune a tree for the most advantage is in mid to late winter. The reason for this is when the weather warms up again and the tree comes out of dormancy, it will stimulate new growth. Before winter comes though when it is still fall, the absence of leaves will help you to quickly distinguish branches that need removal. Most trees in Arizona will not have this issue but be mindful that when tree trimming happens during late winter, certain trees may leak sap. In winter for instance, pruning a maple tree would be desirable, but it can lead to sap bleeding out. However, you do not need worry, as soon as the tree starts bringing on leaves again in the spring, the sap will cease running so it is not harmful, and your tree will not be hurt. While making a pruning plan in the fall is great so you have a game plan, you should still wait a couple of months before actually starting the trimming process as pruning trees can cause disease in the fall. It may also promote fresh development in the event of a warmer than normal fall, which would be destroyed when the temperatures fall.
