Pruning Your Mature Trees

Pruning trees can be one of the most difficult and technical tasks you take on. You prune too much, you risk the tree’s health. Too little and you haven’t done your job.

So why prune when trees in the forest do quite well without it? Although forest trees grow quite well without somebody coming along and trimming them, landscape trees require a higher level of care to maintain their safety and aesthetics. For this reason, pruning must be done with an understanding of how the tree responds to each cut. Improper pruning can cause damage that will last for the life of the tree, or worse, shorten the tree's life. Each cut has the potential to change the growth of the tree and this is why no branch should be removed without a reason.

Although seemingly risky, pruning helps your tree by removing dead branches, prevents crowding or rubbing limbs, and helps eliminate hazards. Trees may also be pruned to increase light and air penetration to the inside of the tree’s crown or to the landscape below. In most cases, mature trees are pruned as a corrective or preventive measure.

There is a difference between pruning and routine thinning. Routine thinning does not necessarily improve the health of a tree. Trees produce a dense crown of leaves to manufacture the sugar used as energy for growth and development. Removal of foliage through pruning can reduce growth and stored energy reserves. Heavy pruning can be a significant health stress for the tree.

Because people and trees have to coexist in urban or suburban settings, we sometimes have to modify the trees for the sake of all. City environments do not mimic natural forest conditions and therefore safety is a major concern. Also, we want trees to complement other landscape plantings and lawns. Proper pruning, with an understanding of tree biology, can maintain good tree health and structure while enhancing the aesthetic and economic values of our landscapes.

So when should one prune is often a common question. As a rule, growth is maximized and wound closure is fastest if pruning takes place before the spring growth flush. Some trees, such as maples and birches, tend to “bleed” if pruned early in the spring. It may be unsightly, but it is of little consequence to the tree. Otherwise, most routine pruning to remove weak, diseased, or dead limbs can be accomplished at any time during the year with little effect on the tree.

Oak wilt can be spread when pruning and wounds allow spores access into the tree. Susceptible trees such as these should not be pruned during active transmission periods.

Heavy pruning just after the spring growth flush should be avoided. At that time, trees have just expended a great deal of energy to produce foliage and early shoot growth. Removal of a large percentage of foliage at that time can stress the tree.

What are pruning terms and techniques? Cleaning is the removal of dead, dying, diseased, crowded, weakly attached, and low-vigor branches from the crown of a tree.

Thinning is the selective removal of branches to increase light penetration and air movement through the crown. Thinning opens the foliage of a tree, reduces weight on heavy limbs, and helps retain the tree’s natural shape.

Raising, removes the lower branches from a tree in order to provide clearance for buildings, vehicles, pedestrians, and vistas.

Reduction reduces the size of a tree, often for clearance of utility lines. Reducing the height or spread of a tree is best accomplished by pruning back the leaders and branch terminals to lateral branches that are large enough to assume the terminal roles (at least one-third the diameter of the cut stem). Compared to topping, reduction helps maintain the form and structural integrity

A common mistake is to remove too much inner foliage and small branches. It is important to maintain an even distribution of foliage along large limbs and in the lower portion of the crown. Over thinning reduces the tree’s sugar production capacity and can create tip-heavy limbs that are prone to failure.

If you are uncomfortable in taking on the task of pruning your own trees, there are professional arborists that know just how much to prune and not to prune as well as a knowledge of proper tree and branch removal.

Andrew Johnson is the owner of Central Texas Tree Care, a leading tree service provider in Central Texas (Travis County and surrounding areas) offering services such as pruning and removals, cabling and bracing as well as arborist reports, diagnostics, pest management, fertilization and Austin tree service trusts. For more information please visit http://www.centraltexastreecare.com.

Tree Pruning Cuts and Techniques

Trees need pruned for a variety of reasons – whether it be for the health of the tree, for safety in regards to limbs interfering with utility wires or potentially falling, or just for the aesthetic of the tree. When pruning your tree there is a science to the procedure. Proper tree pruning cuts and techniques is vital.

To start, where should one begin to prune? Pruning cuts should be made just outside the branch collar. The branch collar contains trunk or parent branch tissue and should not be damaged or removed. If the trunk collar has grown out on a dead limb to be removed, make the cut just beyond the collar. Do not cut the collar.

If a large limb is to be removed, its weight should first be reduced. This is done by making an undercut about 12 to 18 inches from the limb’s point of attachment. Make a second cut from the top, directly above or a few inches farther out on the limb. Doing so removes the limb, leaving the 12- to 18-inch stub. Remove the stub by cutting back to the branch collar. This technique reduces the possibility of tearing the bark.

Many trees form ridges on the top and bottom of branches where they are attached to the trunk. These are called shoulder rings. Pruning cuts should be made between the center ridges of these rings. The cut will not be flush or parallel to the trunk but will be out from it slightly, with the lower edge of the cut farther away from the trunk than the top.

Such a cut will form a smaller wound than a flush cut, and callus tissue will form rapidly to cover the wound. Callus tissue should develop uniformly around the edge of the wound.

Often shoulder rings are not present at branch attachments. The cutting position can be approximated by envisioning a line connecting the point bisecting the top angle of the crotch and a similar point bisecting the lower angle of attachment.

The structural features of a tree may be emphasized by moderate thinning to reduce density. The structure of dogwood, ginkgo and others can be maintained in the landscape by moderate thinning out.

Homeowners often attempt to control the size of trees by pruning. It is best to prune the tree as it begins to reach the desired height. Delaying pruning until the tree is much larger than you want it makes pruning more difficult and pruning cuts harder to hide, and it encourages excessive regrowth.

Thinning-out pruning can be used to reduce the height and spread of a tree. Cut branches to lower laterals (drop crotching). Some limbs may be removed completely. A thinned tree retains its natural shape and is less subject to vigorous water sprouts than a headed or topped tree.

Topping (heading back) is, unfortunately, the most common method of reducing tree size. It is more rapid than thinning, but the results are, in most cases, much less desirable. Regrowth is vigorous and upright from the stubs. The new branches form a compact head and broom-like terminals, and they may be weakly attached to older branches.

Bleeding of pruning wounds can be heavy on certain trees, such as birch, dogwood, sugar maples and elms. Bleeding of susceptible trees can be minimized by making small cuts--less than 3 inches in diameter--and pruning in summer. Bleeding is much more likely if severe pruning is done just before growth begins in the spring. Bleeding doesn't harm the tree, but if it's heavy and persistent, it may injure the bark below the pruning cut and cause slow callusing of the lower wound.

If large limbs need to be removed or if you can't reach the limbs that need pruning, secure the services of a professional landscape manager. Landscape managers are trained in the art of pruning to retain the natural beauty of trees.

Andrew Johnson is the owner of Central Texas Tree Care, a leading tree service provider in Central Texas (Travis County and surrounding areas) offering services such as pruning and removals, cabling and bracing as well as arborist reports, diagnostics, pest management, fertilization and Austin tree service trusts. For more information please visit http://www.centraltexastreecare.com.

Caring For Your Mature Trees

Trees can live for years, even hundreds of years. The oak or walnut can live as long as 200 to 300 years. This means these trees could be witness to up three or four generations of people. A tree of this age has great value and in that also requires great care.

With a little preventative care, your trees can last as long as this. And remember that curing a problem once it develops is much more difficult, time-consuming and costly than preventing one. So isn’t it worthwhile to give your trees regular maintenance to ensure that they are able to offer enjoyment and value for generations to come? If so, lets look at what kind of care a tree needs so that it can grow old graciously.

1. Tree Inspection – To start with your tree’s personal care, you should first have an inspection by a certified professional arborist. Tree inspection is an evaluation tool that will help determine whether the tree is in good or bad health or on the brink of anything disastrous. By providing regular inspections of your trees at least once a year, you can prevent or reduce the severity of future disease, insect, and environmental problems. A professional will evaluate your mature tree for four characteristics of tree vigor: new leaves or buds, leaf size, twig growth, and absence of crown dieback (gradual death of the upper part of the tree).

Any abnormalities found during these inspections, including insect activity and spotted, deformed, discolored, or dead leaves and twigs, will be noted and watched closely. The Arborist or other tree care professional will be able to determine the best solution for the tree’s condition.

2. Mulching - Mulching cools and contains moisture around the tree, which in turn can reduce environmental stress. Mulch can also prevent mechanical damage by keeping machines such as lawn mowers and string trimmers away from the tree’s base.

Mulch should be placed 2 to 4 inches deep around the tree and cover the entire root system, which may be as far as 2 or 3 times the diameter of the branch spread of the tree. If the area and activities happening around the tree do not permit the entire area to be mulched, it is recommended that you mulch as much of the area under the drip line of the tree as possible. When placing mulch, try not to cover the actual trunk of the tree.

3. Fertilization - Trees require certain nutrients (essential elements) to function and grow.
Fertilizing a tree can improve growth; however, if fertilizer is not applied wisely, it may not benefit the tree at all and may even adversely affect the tree. Mature trees making satisfactory growth may not require fertilization. When considering supplemental fertilizer, it is important to know which nutrients are needed and when and how they should be applied.

Soil conditions, especially pH and organic matter content, vary greatly, making the proper selection and use of fertilizer a somewhat complex process. When dealing with a mature tree that provides considerable benefit and value to your landscape, it is worth the time and investment to have the soil tested for nutrient content. Any arborist can arrange to have your soil tested at a soil testing laboratory and can give advice on application rates, timing, and the best blend of fertilizer for each of your trees and other landscape plants.

4. Pruning - Pruning is the most common tree maintenance procedure next to watering. Pruning is often desirable or necessary to remove dead, diseased, or insect-infested branches and to improve tree structure, enhance vigor, or maintain safety. Because each cut has the potential to change the growth of (or cause damage to) a tree, no branch should be removed without a reason.

Removing foliage from a tree has two distinct effects on its growth. Removing leaves reduces photosynthesis and may reduce overall growth. That is why pruning should always be performed sparingly. Over pruning is extremely harmful because without enough leaves, a tree cannot gather and process enough sunlight to survive. However, after pruning, the growth that does occur takes place on fewer shoots, so they tend to grow longer than they would without pruning. Understanding how the tree responds to pruning should assist you when selecting branches for removal.

Maintaining your trees into old age just requires a little patience and care, just like anything. In the end, you will have a beautiful and healthy addition to your landscape and life.

Andrew Johnson is the owner of Central Texas Tree Care, a leading tree service provider in Central Texas (Travis County and surrounding areas) offering services such as pruning and removals, cabling and bracing as well as arborist reports, diagnostics, pest management, fertilization and Austin tree service trusts. For more information please visit http://www.centraltexastreecare.com.