HALLER, J.M. 1981. Practical pruning. Am. Forests 87(9): 11-14.
Pruning is an art as well as a science, and from a distance — since art’s perfection lies in concealing itself — the properly pruned tree should show no evidence of the handiwork that made it what it is. Instead, it should present a graceful, symmetrical shape on all sides and a nearly unbroken surface of foliage. Many believe that a tree should be pruned only in the winter, when dormant. This belief is a carryover from the days when pruning was synonymous with severe topping or dehorning. In cases of dehorning, dormancy is indeed the indicated season. Since in the temperate zones growth occurs most rapidly in the first few weeks of spring and since healing is a form of growth, it follows that pruning cuts made just before spring will begin to heal over almost immediately. Conversely, cuts made in late summer will have to wait until the following spring before healing can begin. On most trees, however, a difference of a few months is not a serious matter, and in practice, pruning crews work all year around. Whether completed pruning cuts should be painted over or left exposed has long been a disputed issue. Personally, until the issue is settled (if it ever is), I continue to use tree seal on all the larger cuts (three inches or more in diameter) for looks if nothing else. A glaring white cut is objectionably conspicuous, but when covered over with tree seal, whose usual color is black, it goes unnoticed.
TATTAR, T.A. 1981. Stress models for trees in the urban environment. Arboric. Journal 5: 55-56.
Stress is common in the urban environment. In the forest ecosystem, trees have evolved means of successfully coping with stress through natural selection. Ability to survive injuries, insect and disease attack, and to compete successfully for limited water, nutrients and sunlight, has been a powerful selective force for ensuring that only the most healthy and vigorous trees would survive. As people began to build cities and towns and to plant trees in them, and environment emerged that was drastically different from the forest ecosystem. The suburban-urban ecosystem, spawned by the technological age, is so new in its evolution that trees have not had time to adapt. It is not surprising that trees are injured and often killed by extremes of soil, moisture, and temperature, by construction, by herbicide misuse, by road salt, and by a whole host of people-pressures.
- © 1982, International Society of Arboriculture. All rights reserved.