Trimming a tree properly only partially depends on the tools and types of cuts. A major part of pruning is the season in which the tree is trimmed. Knowing the seasonal guidelines for general tree trimming can help guide your landscape care calendar.
Early spring is an ideal time for trees that do not flower in the springtime. You may also want to postpone pruning heavy sap-producing trees since sap flows more readily in spring. This is the time of most active growth, so pruning wounds heal quickly. Since foliage isn't yet lush, it is easier to see which branches have poor growth form or didn't survive winter, making it simpler to prune out the right ones.
Summer pruning is primarily for spring flowering trees, which should be pruned as soon as the flowering season has ended. They will quickly begin to form new buds after flowering, so you want to trim them before this occurs so that next year's flowering isn't reduced. You can also prune sappy trees at this time if you missed winter pruning since sap flows less readily in summer. Damaged branches, such as from summer storms, can safely be pruned out of any type of tree during this season.
Fall is the least ideal time to prune a tree, but evergreens, in particular, should not be cut at this time. Pruning an evergreen encourages it to put on new growth. Any tender growth that comes in during fall will be prone to winter temperature damage, which could compromise the health of the whole tree. The only pruning that should be done in fall is removing any badly damaged branches that could pose a hazard. Otherwise, wait until later in the season, and trim only after the tree has gone dormant.
Nearly all trees can be pruned in winter with minimal stress on the tree. The best time is late winter when buds are obviously swollen but before they burst open in early spring, although damaged branches can be pruned out at any time throughout the season. Trimming in winter prevents heavy sap flow due to dormancy, and there are also few insects or pests around to invade a trimming wound. Further, the wound will seal over quickly in the first flush of growth when the tree does break dormancy in spring.
Contact a tree trimming service in your area if you would like more assistance.