Question
We live in Western Pennsylvania and have a crimson maple approximately 12-15 years old that is now about 15-20 feet tall.  It has one branch off the left side that extends above the tree and seems to be in need of pruning to get it growing in a nice shape.  When is it okay to prune this tree and what is the best process?

Answer
While deciduous trees can be pruned anytime during the year, the best time to prune is late winter or early spring before the trees leaf out. Pruning methods are best dictated by your purpose--whether to keep the tree a certain size or shape, or just to tidy it up. Pruning in late summer can encourage new growth which can be cut short at the first frost and impede next spring's growth. In the fall, prune when frost is imminent and leaves are falling. In spring time, prune before new growth is under way. Never prune a tree in mid-growing season because it will be less effective and may shorten the life of the tree.


Prune the dead branch off about 1/4 inch from the trunk. This will leave a branch collar and the wound will heal over by itself. If the wound is more than 6 inches across after the cut I would paint the area with a wound dressing. This will keep water from getting into the wound. On wound less than 6 inches across I would leave natural and not paint.

On large trees it is best to make the first cut about a foot from the trunk on the under side then cut the branch off from the top leaving a stub about a foot long. Then you can prune off the stub and the heavy limb will not split the bark on the trunk.
Here is a web link to how to prune trees with a drawing of the large limb pruning method.
http://www.ces.ncsu.edu/depts/hort/consumer/factsheets/trees-new/text/pruning.ht...