By PAUL HETZLER
Cornell Cooperative Extension of St. Lawrence County
Tree topping is a subject I can really get worked up about. It’s unprofessional, unsightly, outrageous, unethical, dangerous, and probably bears some responsibility for bad breath, rainy weekends and male-pattern baldness. It’s unthinkable, wrong, horrible, bad, yucko, blecch!
Is that pretty clear or are there any questions? Oh, exactly what is topping? Just a minute. Mmmph—there, that’s better. Had to wipe the foam off my mouth.
Tree topping is the removal of limbs, often large ones, to an arbitrary length, leaving long stubs. Variably known as heading, hat-racking or tipping, it’s condemned by the Tree Care Industry of America, the International Society of Arboriculture, and all other professional organizations.
Topping is not to be confused with pollarding, a practice dating to feudal times when a peasant could be killed for cutting down one of the king’s trees, but was allowed to clip each year’s twig extension back to a callus “ball” for use as fuel and fodder. Pollarding works only on certain species, and must be started when a tree is young and continued annually.
Back to topping. It shortens a tree, yes, but doesn’t alter those pesky DNA strands which insist the tree grow to its genetic potential. So the tree re-grows per its DNA instructions. But since all the branch structure has been removed, new branches (epicormic sprouts) erupt right out of the bark. These new sprouts, soon to become major branches, are poorly attached to the parent wood. Not only that, but the tree is in a “hurry” to re-gain its height, and the fast-growing new wood is weaker than the original.
But that is not all—there are two more things. (Do I sound like the Cat in the Hat here?) Thing One is decay, which sets in at every topping wound, and our new, flimsy, poorly-attached branches soon find themselves growing from a hollow stub. It may take thirty years or it may happen in four or five, but every topping cut grows a killer limb. Of the precious few certainties in life, three of them are “death,” “taxes,” and “tree topping creates hazards.”
Thing Two is the budget. A hat-racked tree has to take “money out of the bank” (starch out of storage) to replace leaf-bearing wood at a time when much of its “bank account,” the starch stored in its woody tissues, has been stolen and run through the chipper. Trees use their reserves to make defensive chemicals that protect against pests and decay, to rejuvenate and expand root systems and produce each year’s leaves. A topped tree is left weakened, far more vulnerable to decay, disease, and insects than it had been before its “treatment.”
If a short tree is desired, a short-maturing species should be planted. However, there is an acceptable practice called crown reduction pruning which can slightly reduce the height of hardwood trees safely. Crown reduction takes far more skill and judgment than topping does, and can only reduce a tree’s height twenty-five percent at most.
To address fears about a tree blowing over, there’s a practice, also accepted professionally, called crown thinning. It’s the judicious pruning of branches evenly throughout the canopy to reduce wind resistance. Again, this takes a great deal more skill than topping.
The International Society of Arboriculture, a research and education association of tree care professionals, advises the public that a tree company which advertises topping should not be hired for any work, period. A tree company willing to top trees is by definition less than professional, and less likely to understand other elements of tree care, including basic safety procedures.
Tree topping is acceptable, however, for all who enjoy forty-foot hat racks and liability lawsuits.
Now are there any questions?
Paul Hetzler is a forester and a horticulture and natural resources educator for Cornell Cooperative Extension of St. Lawrence County.