To minimize damage and synchronize with the natural growth cycle, pruning should be done in winter (January, February). Heavy pruning should be avoided as leaves are expanding in early spring when tree energy reserves are low (April, May). Light pruning is less crucial, therefore timing considerations are of less importance. For maximum display of spring flowering, pruning should be done after blooming (June or later). However, dead limbs and branches can be pruned at any time.

When pruning, it is preferable to remove an entire limb or branch rather than to shorten its length. Branches should be cut back to a twig, or twigs to a bud where new growth will resume. Using this technique respects the natural growth pattern of the tree. For branches 1 inch in diameter or larger, pruning should be done in a series of three cuts: an undercut about 5 inches from where the branch meets the tree, a cut above the initial cut to remove the weight of the branch and the finishing cut at the collar of the branch.

Trees produce natural chemicals to prevent decay from entering the tree at the base of each branch or limb. By leaving the slight swelling, or branch collar, at the branch base this chemical zone is preserved. The resulting wound will be smaller than if the branch were cut flush. This rule of thumb applies to both large limbs and small branches. When pruning, it is best to remove only a small percentage of the live part of the tree at a time. A maximum of 25 percent in one year for healthy, vigorous trees should be adhered to. This will help maintain balance between leaf area and other tree functions. It is important that weak or declining trees are pruned even less. Severe pruning may stimulate undesirable sprouting from the stem or roots. Pruning over 25 percent of the live crown of any tree 2 years in succession should be avoided at all costs.

When a tree is young, use simple hand-pruning tools to prevent future structural problems and the need for larger limb removal later in the life of the tree. It is especially important to remove forked tops (double leaders) and to gradually remove lower branches for shade-tree development.

Using the correct tools when pruning is essential in the promotion of a healthy tree. Below is a list of tools and their usefulness:

• Hand pruners – useful in pruning small branches, up to 0.5 inches in diameter.
• Long-handled loppers – used to remove larger diameter branches, although precise cuts are more difficult to make.
• Curved blade pruning saws – these cut on the pull stroke. The newer blade designs are able to cut large and small diameter branches quickly and cleanly. Pruning saws are available with fixed or folding blades, or even mounted on a pole. The larger pruning saws are sometimes used by professionals.
• Chainsaws – Although not recommended for general pruning, professionals sometimes use them as a tree saver.

Consider hiring an arborist for large or potentially dangerous work.