Pruning pears or apple trees can be easy if you follow these techniques during the early years.

It’s best to start with one-year-old plants, called whips. On the day of planting, once they are in the ground, cut them to a height of 3 ½ to 4 feet, or lower if they are dwarfing understocks. During the first two to four years, the goal is to develop well-placed, permanent, scaffold branches, the main framework of the tree. Building this strong structure will allow your tree to support heavy fruit with reduced risk of limb breakage.

Should your tree be two years old at planting time, it will have developed side branches. Prune any branches closer to the ground than 2 feet to a length of 6 inches, the others to one-half their length. In the next year, cut off flush with the trunk the ones previously shortened to 6 inches.

Throughout the early years of training prevent the development of V-shaped crotches that may later be subject to breakage. Do this by shortening severely one of any pair of shoots of about equal size and thickness that form a V of a 45 degree or narrower angle. This will encourage the other to become dominant. And continue to prune so all parts of the tree receive adequate light, crossed or interlaced branches are not allowed to develop, and any sucker shoots from the trunk or main limbs are also removed.

http://www.clemson.edu/extension/hgic/plants/vegetables/tree_fruits_nuts/hgic1351.html

Courtesy of the NYBG Plant Information Service