Douglas L. Airhart & Guy Zimmerman III
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Pruning Trees- Basic Pruning Techniques: First, examine the trunk of the tree. The trunk flare should be plainly visible at soil level, and there should be no sprouts emerging from the flare, nor root suckers from underground near the flare. If root suckers are present, excavate the soil to uncover the base of the sucker and cut it off flush (roots do not have branch collars). Remove any trunk sprouts from the flare, leaving the branch collar intact. Trunks of young trees may have temporary branches between the flare and the lowest limb that will remain. These branches will provide food to help the trunk develop thickness and a good taper from the flare to the leader. They gradually should be removed from the flare upward, one or two per year, as the trunk expands and the canopy develops more branches.
Inspect the general area surrounding the tree for permanent obstructions such as walls or buildings, sidewalks or vehicle parking spaces. Trees planted near streets and intersections must not block driver visibility for oncoming traffic. These obstructions will determine the height to the lowest permanent scaffold branch that will be allowed to grow in that direction, or other directions. Temporary branches below this may remain for two to three years to help develop trunk taper. If no permanent obstructions exist, the height of the lowest permanent branches usually will be determined by mowing equipment, whether you have a walk-behind or riding mower. As the tree matures, leave ample clearance to protect equipment operators from bumping their heads. If you want branches to remain low to the ground, such as on evergreen trees or magnolias, we suggest eliminating grass and plants from under the entire canopy and applying mulch out to the drip line. This will create a no-mow zone and keep the mower from being near the tree and trunk.
Second, examine the canopy of the tree. The first consideration for pruning the canopy of young trees is called the Five D’s. These are branches that can and should be removed at transplanting, or at any time as the tree is maturing. The Five D’s are any branches that are Dead, Dying, Damaged, Diseased and Deformed. The Five D's (prune these branches at any time) Video Vignette (See it live!)
Dead branches are usually easy to identify: they often are brown and brittle, have flaking bark or no bark, and the leaves are gone or dead. Dying branches may be partially dead, usually at the tips, or they may have discolored bark and have brown or wilting leaves in the dying area. Damaged branches could be broken or bent out of shape, have sections of badly scraped bark, or have sections with damage from insect chewing or egg-laying. Diseased branches could have a variety of symptoms such as cankers (sunken portion), discoloration of the bark, wilting leaves, or discolored leaves. It is not in the scope of this tutorial to teach you about all of the tree diseases. We suggest you take a sample to your county extension agent for help identifying a disease. Deformed branches fall into a broad category. They include the stem sprouts and root suckers mentioned in the trunk section above. Three most common types of deformed branches in young trees are double leaders, water sprouts and trunk suckers, and crossing or rubbing branches. Double leaders means the canopy has a very narrow crotch at some point on the trunk with two main growing stems. One of them should be selected become the main leader, and the other should be removed at the branch collar as soon as possible.
Crossing or rubbing branches frequently occur when lateral branches grow from one side of the tree through the center area and protrude out the other side. Generally, long branches that grow across the center of the tree should be removed. If two branches are growing adjacent to one another into the same section of the canopy, they will probably begin to rub against each other and create a bark wound on one or both. Keep the stronger of the two or the one growing in the most appropriate direction, and remove the other at the branch collar before the rubbing causes bark damage. Example: Young Crabapple: Video Vignette- (See it live!) Crabapple trees are notorious for having many of the Five D’s when young and while maturing. They are especially prone to multiple leaders, water sprouts, trunk sprouts and root suckers. The sample crabapple has a typical problem of trees produced at some nurseries, double leaders attached at a very narrow crotch. It has a branch with fire blight, a typical disease in apple trees, and it has crossing branches and root suckers. Most apple trees are grafted onto apple seedling rootstocks, and the rootstocks are usually more vigorous that the cultivated variety that you purchased. This is what makes them prone to having root suckers. Just keep removing them as described in the trunk section, above. | ... |
Purpose Right Tree / Right Place Selecting Trees Transplanting Trees Mulching & Staking Summary Diagram Pruning Trees Topping Hurts! Protecting Trees Tree Root Myths Pine Bark Beetles Live Christmas Trees Glossary List of Figures List of Video Vignettes Related Links Bibliography
TLCforTrees.info is maintained by: Douglas Airhart, Ph.D. Certified Arborist & Jeff Plant, Ph.D, Last Updated on: 07/11/03 |
