Generally, fruit trees are pruned to develop a desired tree shape, to maintain the tree at a desired size, to make spraying easier, to improve fruit quality, to improve tree strength and induce branching, and to improve air circulation within the tree, which will reduce the potential for disease. Excessive pruning encourages excessive shoot growth and reduces the quality of fruit on young trees. Older trees (25 years and older) will produce higher-quality fruit following a vigorous pruning.
Regardless of the type of tree you are pruning, there are only two types of pruning cuts. The first is a heading cut. This type of cut involves shortening a limb or shoot by removing a portion off the end. Heading cuts remove the terminal buds that normally inhibit shoot development from buds below the terminal or end of the shoot. A heading cut results in several shoots developing just below the location of the cut. The number of shoots that develop and the vigor of the growth will depend on the severity of the heading cut. Heading cuts result in a thicker and denser canopy and reduce light levels within the tree.
The second is a thinning cut. A thinning cut is the removal of an entire shoot back to its point of origin. Thinning cuts do not induce excessive vigorous regrowth and open the tree's canopy to allow more sunlight into the interior. The image above illustrates the growth that occurs when a dormant shoot (A) is not headed, (B) is headed one-third of its length; (C) is headed two-thirds of its length, or (D) is headed to remove all of the previous year's growth. Note the increase in vigor and reduction in fruiting wood the more severe the cut.
Prune young trees (up to 10 years of age) lightly. Prune older trees more vigorously. Be sure to remove all dead and broken limbs when you prune. Remove sucker growth from the interior of the tree and around the base of the trunk annually. Thinning-out cutting (removing an entire limb or shoot) is associated with increased apple flower bud production. Heading-back cutting (shortening the ends of branches) encourages shoot growth. Remove pruned brush from the orchard area. Dead wood will harbor disease organisms that can spread back into the tree. Burning or burying the prunings is the best practice.