The most attractive of landscape trees are the ones that are kept neatly trimmed and pruned. Not only will this help keep the trees a manageable size, but it will also keep them creating new growth and keep them from overwhelming surrounding plants and trees. Maple trees are a common sight in the northeastern United States and they'll look even better in your yard when you learn how to keep them trimmed and pruned.
Choose when you're going to prune. Since maple trees bleed sap when their branches are cut, the best time to prune is when the leaves have fully matured. At this time, there will be less sap.
Remove all dead or dying branches. Do this before you start cutting live branches; it will give you a better idea of what your tree looks like and how many of the live branches you're going to need to cut.
Decide which branches you're going to cut before you start cutting. There are some that will be more susceptible to breaking. Look for large branches growing at narrow angles to the main trunk, branches that are rubbing others or branches that are growing inward and crossing others.
Remove the larger branches. To do this, make the first cut all the way through the branch, at least a foot from the main tree trunk. Use two cuts; the first should begin underneath the branch and go upwards, with the second starting on the top and going down to meet the first. With the weight gone, you can finish cutting the remainder of the branch without struggling with the extra length of the branch. To keep the bark from peeling, remove the stub of the branch with a single cut going down and away from the tree trunk.
When pruning larger branches, make sure you don't leave a stub. Leaving the stub can invite rot and disease. Always trim back to the main trunk or one of the larger lateral branches. When pruning some of the smaller branches, cut back to a bud. When cutting back to a bud, cut at a slight angle above the bud. This will speed the healing process.
Thin some of the smaller branches. Use your best judgment. You're trying to increase the amount of light that gets through the foliage while maintaining the tree's natural shape. For mature maple trees, you shouldn't need to remove too many of these branches.
Keep your pruning tools sharp, whether you do this yourself or have it done professionally. A dull blade will not only make your job more difficult, but it'll damage your trees. While you're pruning, it's a great time to inspect leaves and bark for signs of insect infestation or disease.
Don't prune right after the leaves have come out. The tree has already expended a lot of energy in the process and forcing it to heal after cutting branches will put even more stress on the tree.