Topping: The Most Expensive Form of Pruning

By Alden Kelley

Without a concerted, sustained effort to counteract topping as a trend in the tree care business today, the image and financial base of the profession at large will be affected by those who operate at the low end of the quality scale.

Topping, also called heading, or hatracking, refers to the removal of major portions of a tree crown by cutting branches to stubs and/or to the trunk. Topping severely injures and infects trees. It sometimes kills them outright. Nonetheless, the procedure appears to be on the increase worldwide.

Why would a client ask to have a tree topped? There seem to be three main motivations: 1) concern about tree size and the possibility of blowdown or line breakage, 2) a misguided intent to save money -- a low-bid policy in the absence of clear, definition of pruning method, and 3) acceptance of the method due to its obvious practice by many professionals.

Unfortunately, correctly pruned trees are not often apparent to the untrained eye, whereas topped trees are starkly conspicuous. Thus the examples of quality tree care frequently go unnoticed while the mutilated victims of topping specialists serve as the public's model of professional standards.

With this guiding image, it is little wonder people specify topping to reduce the damage potential of trees, particularly when it is the cheaper way to allay their fears.

When a client requests topping of trees, some professionals will do it because they don't know any other way to trim trees. Some will do the work on the grounds that they will lose the bid otherwise. Others will argue against topping (and risk losing the contract) on the basis of professional integrity.

It is chiefly in the latter group for whom this report is written. This information is offered to help explain the biological and economic costs of topping, while showing the immediate and long-term benefits of high-quality pruning. The purpose is to show clients that everyone profits from correct pruning, whereas the only person to gain from topping is the topping specialist.

Tree Responses to Topping

Normal apical control of growth and form is eliminated. Released from natural suppression, latent buds frequently emerge in large numbers, producing clusters of shoots below the stub cuts. These shoots are characterized by some or all of the following features: close placement, which soon results in bark between branch bases; narrow crotch angles; growth toward the center of the crown; frequent crossing branches; and shallow branch attachments, which leave the branches vulnerable to breakage.

The intact root system continues to provide water and minerals at the level previously required by the whole crown. This stimulates the excessive growth of new shoots, often forcing them to grow rapidly which can result in long, thin, brittle branches.

Summer topping can thrust the tree into an unseasonal growth flush, upsetting its annual rhythm and leaving it susceptible to further injury from low temperatures in autumn.

Topping (or any stub cut) disrupts all the longitudinal compartments of a woody stem, maximizing exposure to insects and disease organisms while minimizing the tree's capability either to resist them or to produce effective wound closure.

The root system depends on leaves or storage reserves for its energy supply. Topping not only eliminates much of the foliage, it prevents the roots from obtaining stored food. The rapid branch growth following topping depletes the remaining reserves. Only after new growth slows down markedly can the leaves again supply sugars to nourish the comparatively remote root system. This weakens the root system, increasing its susceptibility to rot and accelerating the overall decline of the tree.

Exposure and trauma from topping will frequently set the stage for sunscald and/or cold damage.

The natural form of the tree is destroyed. Even with careful repeated restorative pruning, the tree can never be brought back to its original potential for beauty and normal shape for the species.

Because of the radical disorganization of physical and chemical processes caused by topping, even when a tree does not die immediately its life expectancy is sharply reduced.

Some clients may not accept these facts as a sufficient argument against the price difference between topping and fine pruning. However, the following information usually has a telling effect.

Effect of Pruning Method on Tree Value

The real estate value of trees can be assessed by the procedures set forth in Guide for Establishing Values of Trees and Other Plants 6th edition. International Society of Arboriculture Urbana, IL 1983.

The value of transplantable trees is based on replacement cost. For trees too large to transplant (i.e. 12 inches or more DBH) formulas are given for evaluation in terms of four factors: size, species, location and condition.

The condition factor is directly altered by pruning, resulting in an immediate change in the tree's assessed value.

Class I fine-pruning (National Arborist Association standards), using Dr. Alex Shigo's natural target pruning method, always enhances tree value. This usually increases the worth of a tree by five to 15 percent typically ten percent.

Topping always lowers tree value by at least 20 percent, frequently 50 percent or more, sometimes 100 percent. A 35 percent value loss would be very conservative.

Consider the net effect of each method on an unpruned tree valued at $1,000, with contract figures of $200 for fine pruning versus $100 for topping. Fine pruning at $200, increasing the tree value by $100 (10 percent of $1,000), would have a net cost of $100. Topping for a contract price of $100, resulting in a $350 loss in value (35 percent of $1,000), would have a true cost of $450.

The difference in the tree's value spread will increase with each passing year. It can take five or ten years for a topped tree just to return to its former value. On the other hand, a correctly trimmed tree increases in value between prunings, and immediately increases further in value at each pruning.

By the same token, most topping devaluation exceeds the 35 percent mean value suggested. As a general observation one can assert that every $100 invested in topping trees is followed by a $200 to $1000 or greater loss in property value. Obviously, topping is not a bargain at any price.

Nationwide, the annual property depreciation due to topping may well exceed a billion dollars. This does not include the environmental loss from defoliation of millions of trees by "chain saw blight" or the expenditure of money and labor required to remove and replace trees prematurely dead because of topping.

The issue of quality pruning versus topping is one of biological concerns, economic consequences and professional ethics. Those who ignore these matters and top trees as a matter of course or because someone else will get the contract if they don't top, assure long-term loss to everyone.

Within the industry, topping sets the lowest standard for both quality and price. The result is that the profit margin for quality work (which is far narrower than that for topping) is held to a minimal range.

The only way you can maintain a competitive contract structure and still do quality work is to teach your prospects and clients the real costs and benefits of proper pruning methods. Show them how to specify work to exclude topping and other forms of stub cutting. If bids are based upon Class 1 fine pruning specifications, there will be no option available to the topping specialist. The low bid process will thereby lead to fair competition between quality workers, giving a return which can properly compensate high standards of tree care.

Beyond educating people in recognizing and specifying proper pruning methods, it is important to work with other professionals and your own crews to be certain that knowledge and application reflect the highest standards. Through teaching by words and examples, we can change the trend toward topping into a pattern of ethical, high-level professionalism in the tree care industry. Let's substitute quality pruning for destructive topping!

Specifications for Pruning

The most reliable means to ensure fair price competition for quality work is clear specification of pruning details. Because most tree owners have little perception of pruning standards, it can be to your advantage as well as to theirs to provide them with a guide to specifications.

Specifications should cover most of the conditions encountered. By providing the prospective client with pruning standards you enable him to designate high quality in the bid offer. This will automatically eliminate topping as an option, allowing you to bid at a level appropriate to the quality of workmanship.

The following standards are for Class I fine pruning. If a given project is specified at another level, e.g. Class II medium pruning, obviously those standards would prevail.

Safety Measures

Worker Safety

Workers shall wear hats; climbers shall use tree saddles and safety lanyards, and also a safety line with rappelling hitch for climbing at heights above 15 feet. Ground workers shall stand clear of branch drop areas and take appropriate precautions to avoid injury from the work or tools employed.

Protection of People and Property

Tree pruning or removal performed in the vicinity of pedestrian or vehicular trafficways shall be effectively cordoned off with pylons and/or lines, and shall have warning signs to keep people at a safe distance from the work area.

Branch drop after cutting shall be controlled to avoid injury to people and property. Branches too large for controlled, one-handed dropping shall be roped and lowered by ropes or other equipment.

All brush and other trimming debris shall be cleaned up and removed from the site, leaving a safe and neat ground surface upon completion of the work.

Tree Care

Three cuts should he employed for removing branches too large for one-handed holding. The first cut should be an undercut 1/4 to 1/2 the branch thickness, six to 12 inches from the branch base. A second cut within an inch or two of the first should be made to drop the branch. A final cut should be made at the edge of the branch collar to remove the branch stub.

No stubs will be left at the end of the pruning operation. No climbing spike (gaff climbers) or devices injurious to trees shall be used on living trees.

No branch should be cut flush with the trunk or mother branch; the branch collar shall be preserved intact.

Style of Cut

After the final cut in lateral branch removal a protuberance is left. The angle of the cut needed to save the branch collar is determined by natural target pruning. This angle is equal and opposite to the angle of the branch bark ridge when present. When the branch bark ridge is not visible, the angle is determined by the swelling at the branch trunk union. The resulting knob or bump, which is called branch collar, is neither a stub nor, a flush cut.

For thinning or crown reduction, a terminal shall be cut back to a lateral. This lateral must be oriented to maintain the natural shape of the tree (e.g. not growing toward the interior of the crown). The basal diameter of the lateral must be at least 1/3 the basal diameter of the terminal at the point of removal.

The final cut in removal of a terminal branch shall preserve the entire branch collar of the remaining lateral; the angle of the cut shall parallel the upper angle of the remaining lateral.

Pruning Functions

Each of the following shall be performed to whatever extent is appropriate for preserving the soundness, landscape, function, beauty, form and safeness of each tree.

Clearing

Branches shall be removed, and growth redirected as needed to clear pedestrian and vehicular traffic areas, buildings and other structures, as well as other trees and shrubs.

Cosmetic and Hygienic Pruning

The trimming operation shall include removal of dead, broken, and unsafe branches, as well as shrubs remaining from prior pruning.

Structural Corrections

Crossing branches that present current or future surface contact should be corrected by removing the least desirable branch. Shoots which are expected to become crossing branches (such as stickers, water sprouts or inward-growing shoots) shall be removed. Exceptions are interior branches needed to provide shading of trunk or interior branch bases.

Sharp Angled Branches

When structural weakness is apparent in branch bases arising at angles of less than 30 degrees, those branches shall be removed or lightened to curb breakage hazards.

Parallel Branches

If two branches within 15 inches of each other are parallel for several feet along their main stems, the less desirable one shall be removed.

Pruning for Shape

Trees with abnormal, unsafe or unattractive imbalance should be pruned to resemble a normal shape for the particular variety. Trees which are trained as espaliers, hedges, sheared forms, or picturesque styles shall be pruned in a fashion to maintain the intended effect.

Pruning to Reduce Wind Resistance

Canopy Thinning

If foliage density still constitutes a wind breakage hazard after the preceding steps have been completed, the necessary thinning cuts and removal of laterals shall be done in a way which retains the natural form. Numerous small branches will be removed, rather than a lesser number of larger branches.

Crown Reduction

If density and height of the upper crown present a breakage risk which cannot be relieved by canopy thinning, the upper crown shall be removed by drop crotch pruning to establish a natural appearing lower crown through retention of suitable laterals.

Size Reduction

If necessary for size control, the upper crown and/or horizontal branches shall be restricted by means of drop crotch pruning. When feasible, smaller terminals will be removed in preference to larger ones.

When top and/or root growth must be restricted to protect surface structures or when formal shape is desired, shearing shall be performed one to four times annually, as necessitated by existing conditions.

These specifications could be incorporated into a standard bid specification form. Alternatively, certain portions could be excerpted for specific applications. Whatever approach is used, detailed are the best insurance for high-quality tree care provided at a fair and reasonable return to the operator.

Editor's Note: Alden Kelley is employed by Knapp Tree Service, Riverside, California.

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