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TREE-PRUNING TESTS YOUR JUDGMENT

Teaching in pruning demonstrations makes me feel more like a behavioral scientist than like a horticulturist. The most difficult skill to acquire when pruning fruit trees is not the horticultural knowledge but the ability to make decisions. Many pruners spend most of their time agonizing over those branches to cut and those to leave. Learning what to cut and what to leave makes the process much easier.

Pruning is defined as removing certain parts of the tree in order to regulate the shape and habits of the tree and the quality of the fruit. Pruning should be done with a minimum of interference to the natural growth of the tree. Certain basic principles apply to pruning all fruit trees. Let me stress that guidelines here apply only to fruit trees not shade trees. They are pruned heavily each year to force them to produce adequate fruiting wood. Fruit-tree pruning requires long-handled pruning shears or loppers. Hand pruners are used on small limbs 1/2 inch in diameter or smaller and are useful on peach trees. Larger cuts require a pruning saw. These saws have thin blades, coarse teeth and generally cut on the pull stroke. Properly trained trees should never require chain saws for pruning, but occasionally on long-neglected trees, even these saws have their use.

There are two basic training systems for newly planted trees. The first is the central leader tree that develops a pyramidal "Christmas tree" shape. It is used for apples, pears and other fruits. The other system, the open center or vase-shaped system, is used primarily on peach trees. These systems are used to train young trees, not torenovate old trees that have been previously trained to another system or neglected for long periods.

The central leader system develops a main trunk and layers or whorls of branches off the trunk. Each layer is about 2 feet above the one below it and is one year younger. Newly planted trees are cut to a height of 30 inches to force branching. The top bud is allowed to continue to grow to be the central leader. Four side branches are allowed to develop and grow to the four points of the compass. A branch going directly south is usually desirable as it shades the trunk of the tree and protects it from sunburn.

Care should be taken that the branches are not too upright. Wood or metal spreaders are often placed between the branch and the trunk to give an angle of approximately 60 degrees from vertical. This gives wide angles that develop strong branches and forces the tree into early production. Continue to develop the layers of branches until there are three or four sets, one above the other.

Strong, well-pruned trees are a great asset to the backyard orchard. They support the fruit load without props, ropes or other inventions that emerge to keep improperly pruned trees from breaking down.

Peach and nectarine trees are trained to an open center or vase configuration. This training system develops three to four scaffold branches arising near each other on the trunk. The scaffold branches radiate from a common point on the trunk, 18 to 24 inches from the ground. Cut peach trees back to this height when first planted to force these branches to grow. It is most desirable to buy small, 1-year-old whips, rather than large, more mature trees. These larger trees develop their branches 4 to 5 feet off the ground. These top-heavy trees are more likely to break the trunk when a full crop of fruit is produced.

Peaches require heavy, annual pruning to force production of 1-year-old wood that fruits the following year. Failure to prune peaches properly results in small fruit or weak, short-lived trees. The center of the tree is kept reasonably open to maintain the spreading form and allow good light penetration. Avoid climbing in peach trees while pruning because the bark is easily scuffed or damaged. This results in open wounds where canker or infections enter the tree. Combined written material and demonstrations teach good pruning practices. Gird up your courage, learn to make the decisions, and prune trees correctly. The reward is strong, healthy trees and an abundance of high quality fruit throughout the growing season.

- OUTDOOR FRUIT TREE AND BERRY PRUNING DEMONSTRATION, Saturday, March 14, at 11 a.m. or 1 p.m., 815 E. Vine St., Murray.

- SMALL FRUITS: Growing raspberries, strawberries and grapes in the home garden. Thursday, March 19, 2-4:30 p.m. or 7-9:30 p.m., 2001 S. State, Room S1007.

- LANDSCAPE DESIGN - FOUR WEEK COURSE, April 9, 16, 23, 30, Thursdays, 2-4:30 p.m. or 7-9:30 p.m., 2001 S. State, Room S1007. Preregister by calling 468-3170. Seating is limited so register now. $10 fee for handouts and materials.

- ANNUAL BULB AUCTION MARCH 13: The annual bulb auction of the Utah Gladiolus Society will be held at the Sugarhouse Park Garden Center, 1602 E. 2100 South, Friday, March 13 at 7 p.m.