HOW to Prune Trees Page 1 of 4 Prune Trees P;;;~\United St;ltas Preparf)d by Northeastern Area ;\WJJ Dopartmentof Forest Sel\lico State s Pririille '<~- Agriculture Forestry, NA..fR41oSS Introduction Reasons for pruning Pruning approaches Crown thinning Crown raising Crown reduction Pruning cuts Pruning living branches Pruning dead branches Drop crotch cuts Pruning_practices that harm trees When to prune Pruning tools Table of Contents. httn-//www n;l f<;:. fp:nll<;:./<;:.nfn/nllh,,/hnwtn,,/ht nmnp/nnmnn I htm 4l1nnnr.
. HOW to Prune Trees Page 2 of 4 Treating wounds Pruning guidelines General Crown thinning Crown raising Crown reduction Glossary References Northeastern Area State and Private Forestry Offices Authors Introduction The objective of pruning is to produce strong, healthy, attractive plants. By understanding how, when and why to prune, and by following a few simple principles, this objective can be achieved. Reasons For Pruning The main reasons for pruning ornamental and shade trees include safety, health, and aesthetics. In addition, pruning can be used to stimulate fruit production and increase the value of timber. Pruning for safety (Fig. la) involves removing branches that could fall and cause injury or property damage, trimming branches that interfere with lines of sight on streets or driveways, and removing branches that grow into utility lines. Safety pruning can be largely avoided by carefully choosing species that will not grow beyond the space available to them, and have strength and form characteristics that are suited to the site. Pruning for health (Fig. IB) involves removing diseased or insect-infested wood, thinning the crown to increase airflow and reduce some pest problems, and removing crossing and rubbing branches. Pruning can best be used to encourage trees to develop a strong structure and reduce the likelihood of damage during severe weather. Removing broken or damaged limbs encourages wound closure. Pruning for aesthetics (Fig. IC) involves enhancing the natural form and character of trees or stimulating flower production. Pruning for form can be especially important on open-grown trees that do very little self-pruning.. htto:llwww.na.fs.fed.us/sofo/nuhs/howtos/ht nmne/nnmool htm
, httnj/www na fs ff':rl ll.,,/5'nfn/nllhs/hnwtm/ht nmnp/rl1to;: htm -_. - ---------- HOW to Prune Trees Page 1 of 2 Pruning Cuts Pruning cuts should be made so that only branch tissue is removed and stem tissue is not damaged. At the point where the branch attaches to the stem, branch and stem tissues remain separate, but are contiguous. If only branch tissues are cut when pruning, the stem tissues of the tree will probably not become decayed, and the wound will seal more effecti vely. 1. Pruning living branches (Fig. 6) To find the proper place to cut a branch, look for the branch collar that grows from the stem tissue at the underside of the base of the branch (Fig. 6A). On the upper surface, there is usually a branch bark ridge that runs (more or less) parallel to the branch angle, along the. stem of the tree. A proper pruning cut does not damage either the branch bark ridge or the branch collar. A proper cut begins just outside the branch bark ridge and angles down away from the stem of the tree, avoiding injury to the branch collar (Fig. 6B). Make the cut as close as possible to the stem in the branch axil, but outside the branch bark ridge, so that stem tissue is not injured and the wound can seal in the shortest time possible. If the cut is too far from the stem, leaving a branch stub, the branch tissue usually dies and woundwood forms from the stem tissue. Wound closure is delayed because the woundwood must seal over the stub that was left. Figure GA.Targeting the cut., cut t,... n;!at B. Cutting a small C. CutHng a larger branch branch ~~~. 2nd ~.~~ "'~"~;~ 1st cut The quality of pruning cuts can be evaluated by examining pruning wounds after one growing season. A concentric ring of woundwood will form from proper pruning cuts (Fig. 6B). Flush ~uts made inside the branch bark ridge or branch collar, result in pronounced development of woundwood on the sides of the pruning wounds with very little woundwood forming on the top or bottom (Fig. 7D). As described above, stub cuts result in the death of the remaining branch and woundwood forms around the base from stem tissues. When pruning small branches with hand pruners, make sure the tools are sharp enough to cut the branches cleanly without tearing. Branches large enough to require saws should be supported with one hand while the cuts are made. If the branch is too large to support, make a three-step pruning cut to prevent bark ripping (Fig. 6C). 1. The first cut is a shallow notch made on the underside of the branch, outside the branch
HOW to Prune Trees Page 1 of 1 Pruning Practices That Harm Trees Touning and tipping (Fig. 7A, 7B) are pruning practices that harm trees and should not be used. Crown reduction pruning is the preferred method to reduce the size or height of the crown of a tree, but is rarely needed and should be used infrequently. Topping, the pruning of large upright branches between nodes, is sometimes done to reduce the height of a tree (Fig. 7A). Tipping is the. practice of cutting lateral branches between nodes (Fig. 7B) to reduce crown width. These practices invariably result in the development of epicormic sprouts, or in the death of the cut branch back to the next lateral branch below. These epicormic sprouts are weakly attached to the stem and eventually will be supported by a decaying branch. Improper pruning cuts cause unnecessary injury and bark ripping (Fig. 7C). Flush cuts injure stem tissues and can result in decay (Fig. 7D). Stub cuts delay wound closure and can provide entry to canker fungi that kill the cambium, delaying or preventing woundwood formation (Fig.7E). Figure 7. Practices that harm trees hltn://www n::j f" ff'rlll(d~nfn/nl1h<:/hnultn"/ht nrllnp/h<1rtrl htm An ''"')(\(\/-. -----
I' How to rufle YOUflS "As the twigis bent, so is the tree inclined," This insightful saying about education also serves as the. cardinal principle for pruning trees. How you prune your tree during its first few years will affect its shape, strength, and life span. Proper pruning will save you money and give you safer, healthier, more. beautiful, and easier-to-maintain trees. KeystoGood Pruning 1. Prune early in the tree's life so pruning wounds are small, but do not start until the third year or so. A new transplant needs its leaves to produce for new growth. 2. Identify the best leader and lateral branches before you begin pruning and remove any defectiveparts before pruning to forni.try to find and use lateral branches that form "10 o'clock"or "2 o'clock"angles with the trunk, Branches with such angles will have greater strength than those with sharper angles; 3. Keep your pruning tools sharp. One hand pruning shears with curved blades work best on young trees. Prune with an eye to the future, As you prune, remember that the branches do not move up the trunk as the tree grows. A branch 5 feet from the ground now will be 5 feet offthe ground in 10 years-onlythicker and longer than it is now. Try to visualize what a particular branch will look like later, and remove any branches that will cause an obvious problem. Never remove more than one-third of a tree's crown, and always try to maintain at least two-thirds of the tree height as live crown. Prune otf water sprouts in the crown shade trees How to Make a Pruning Cut Pruning Large Umbs:. Large. heavy limbs could' tear loose during pruning. stripping bark and creating jagged edges that invite insects anddisease. That won't happen if you follow these steps. Pruning Smaller Branches: Thin out branches for more even spacing Make a ilnal cut next to the trunk, just outside the branch collar, wiih the lower edge farther away from Ihe trunk than at the top. Smaller branches should be cut just beyond a lateral bud or another small lateral branch. The ideal cut is sharp and clean, and made on a slinht-angle" (\ /~~t"~r, / <,. I;' \ \ / r : \, r, Correct.:roo \. \ Pruning /Ctose C~ / I \ \ /-' /,/. Double Leaders Cut part way ihrough the branch from.beneath. Make a second cut on the' top of the branch, several, inches cut from tile first cut. This will allow the 11mbto fall and be.safely removed. Selecta single..' leader and protect','" it from competition, Removecodominantleaders that have crooks or other defects, Too Slanted Cut off suckers - Remove any branches that rub others or are growing in an undesirable direction <,...;:...... 1... I' -< ---.;..1,.,~ Waterspouts & Suckers Tree as planted 16 By age 3-4 years Prune oit lower branches to raise crow~~~~, '" -'~"'-'i"--:;:~~'" By age ;-7 years "."i:il.. '''=''''''';''f' SuckersandwaterspoUts'are rapidly growing, weakly attachedbranchesihat can occur at the base or in the crown. Removethem as soonas possible. 17