Pruning Benefits and Timing
Keep your trees properly pruned for:
- Health: Remove dead, diseased or dangerous branches.
- Convenience: Keep trees from interfering with pedestrians, vehicles or structures.
- Longevity: Correct a tree’s structure so branches and limbs are less prone to damage.
When should you prune a tree? It depends on the type of tree:
- Evergreen Trees: Prune them anytime.
- Deciduous Trees: It’s best to prune deciduous trees when they're dormant. Their store of energy is in the roots, not in the limbs and leaves you’re removing. It's also easier to see the structure of a dormant tree.
- Exceptions: Remove dead, diseased and potentially harmful branches at your earliest convenience.
Tree Shaping: Pruning Cuts
When deciding how to shape a tree, there are several key points to keep in mind. To prevent injury to the tree, remove large branches in three steps: with an undercut, overcut and finished cut. Here’s how to cut off tree branches safely.
Make Three Cuts
Avoid pruning oak trees while they’re actively growing. Fresh wounds can attract beetles that carry oak wilt disease.
Pruning Branches at a Weak Crotch
With trees, the narrower the angle, the weaker the limb. The V-shaped crotch in the image to the right could pose a problem as the tree grows larger — perhaps tearing off in a storm. Better to use a hand saw now than a chainsaw later.
The image to the right shows what the tree should look like after the limb is removed. Note the angle of the cut, which results in a smaller wound that'll heal quicker than a flush cut.
Pruning Water Sprouts and Sucker Shoots
Some species send out rapid-growing juvenile shoots wherever bark is injured or previous pruning has occurred. Water sprouts grow on limbs and branches, sucker shoots from the base of the tree. They're unsightly (and unnecessary to the tree).
Tree Pruning Advice: Correct Pruning Cuts
A common pruning mistake is to leave a stub. It not only looks unattractive but the stub will eventually die, becoming a home to insects as it disintegrates.
The proper cut, shown in the image to the right, mirrors the angle of the included bark (see arrow). Included bark, seen here as a dark, slightly ridged seam, forms when two or more branches grow closely together. It’s usually a sign of a weak joint.
Dealing With Multiple Leaders
Some smaller trees, such as a Japanese maple or a smoke tree, look good with multiple leaders, where there's more than one main upright limb. But it can be a recipe for disaster with trees that grow large, such as the elm pictured at the right. As the limbs become larger and heavier, the connection to the tree will become weaker. Eventually, wind, ice or some other outside force will cause the trunk to split, and the tree will likely be lost. It’s important to take all of this into consideration when pruning large trees.
Take care of the problem early, before there’s any damage. Choose the taller and straighter of the co-dominant stems and remove the other.
