Annual maintenance pruning, especially on fruit trees, will open the canopy, and prevent crowding and branches from impacting each other. This will allow better air circulation and sunlight penetration, reduce disease problems and often result in a better yield of higher-quality fruit.
Annual maintenance pruning also reduces another concern for the homeowner: branch shedding. Some species, such as cottonwood (Populus deltoides), are notorious for branch drop, but most species are prone to it when competition for light is intense. Branches that do not produce enough carbohydrate from photosynthesis to maintain themselves will die and eventually fall from the tree. Where the break is clean, wound wood or callus is formed, preventing rot; where the break is a tear or rip from high winds or heavy rain, the wound seldom heals properly, shortening the tree's useful life. Annual maintenance pruning can identify those branches that may be prone to breakage, permitting proper removal.
Most deciduous trees have spherical or decurrent crowns with many lateral branches that may compete for apical dominance. If two branches are competing for dominance (co-dominance), the result often is a weak union between the two. That means the tree likely will tear apart in the future. Remove the weaker of the two branches when it still is small and can be removed with a hand pruner or lopper to assure a single dominant stem.