My experience in pruning fruit trees has been limited to trees I have grown in backyards wherever I've lived.
Pruning fruit trees is different from ornamentals because the purpose is to encourage fruiting, having a branching structure strong enough to support fruit, and limiting the tree's overall height so picking and spraying can be done easily.
Begin by removing the obvious problems. Water spouts, crossing limbs, damage and branches growing in any undesirable directions. With pruning it helps to understand how fruit trees produce. Apples produce flowers and fruit on spurs that are at least 2 years old. Each year a spur puts out blossoms, forms fruit and grows a little longer to repeat again the next year. These spurs can produce for many years.
Apricots produce on short spurs that form one year and begin producing the next year. Production will continue on the same spurs for about three years. So by removing the played out spurs, the tree is continually growing new branches with fruiting spurs.
Peach trees need to be pruned rather heavily, as much as 2/3's of the previous year's growth. Prune by cutting every 2 out of 3 branches, or cutting branches back to 1/3 their length. The fruit sets on year-old stems. If not pruned, the branches get further away from the tree's center, setting fruit further and further out, weighing down the branches.
Cherries bear fruit on long-lived spurs, so prune the tree for overall health and shape. Pears also produce fruit on short spurs that are productive for many years. Pear trees tend to grow many upright stems, crowding the tree's center. Remove most of those limbs and prune the treetop to allow light into the tree.
Plum and prune trees bear fruit on lateral spurs, beginning after one year's growth and continuing for many years. These trees should be pruned to prevent limb ends from getting too heavy with fruit and damaging the tree. European plum varieties require less pruning than the Japanese plum trees, which are more vigorous growers producing many long new shoots each year.
An important consideration to having a home orchard in this area is the necessity to be diligent in the prevention of pests and to maintain a tree-spraying routine. Get yourself a pruning book. They are chock full of diagrams and illustrations and who doesn't prefer looking at pictures?
Joan Heihn of Hermiston is a gardening enthusiast and OSU/Umatilla County Master Gardener. Readers may e-mail her at firstname.lastname@example.org.