Here is part of a report on 7 maples topped to death:
APPENDIX #1: MATURE TREE PRUNING
Regarding the correct time of year to prune trees, late summer is a good time to prune hardwoods such as maples if the pruning is done according to industry standards, as Dr. JC Raulston taught in his Physiology of Landscape Plants at North Carolina State University in 1987. The trees have a chance to start sealing their wounds before they go dormant, and there is little time for insects to enter the tree before they too go dormant.
Late summer is also a time when trees are preparing to send their energy in the form of chemical compounds to their root systems to be stored and synthesized into new compounds for their use. Much of that energy still in the leaves, twigs and branches. Therefore when all these parts are removed during the growing season, the trees have few resources out of which to make new leaves the next spring.
The American National Standards Institute defines “Tree topping” as “ The reduction of a tree’s size using heading cuts that shorten limbs or branches back to a predetermined crown limit. Topping is not an acceptable pruning practice.”
The type of heading cuts used on eight mature sugar maple, Acer saccharum, trees on the homesite is defined by ANSI as “Cutting an older branch or stem back to a lateral branch not large enough to assume apical dominance in order to meet a defined structural objective.” ANSI A300 Standards relevant to the September 2001 tree work at the homesite follow:
SAFETY 2.3.1 Tree Maintenance shall be performed only by arborists or arborist trainees who, through related training or on-the-job experience, or both, are familiar with the practices and hazards of arboriculture and the equipment used in such operations.
PRUNING CUTS 5.3.6 Tree branches shall be removed in such a manner so as to not cause damage to other parts of the tree or to other plants or property. Branches too large to support with one hand shall be precut to avoid splitting of the wood or tearing of the bark…Where necessary, ropes or other equipment shall be used to lower large branches or portions of branches to the ground.
PRUNING OBJECTIVES 5.5.2 To obtain the defined objective, the growth cycles and structure of individual species and the type of pruning to be performed should be considered.
5.5.3 Not more than 25% of the foliage should be removed within an annual growing season. (As the photographs show, almost 100% of the foliage was removed—ed.)
5.5.4 Not more than 25% of the foliage of a branch or limb should be removed when it is cut back to a lateral.
5.5.7 Topping and lion’s tailing shall be considered unacceptable pruning practices for trees.
ANSI Standards are widely available to all. The Standards referenced above were printed in 2000, with few changes made to the 1995 Standards. Many other agencies have issued publications condemning the topping of trees. Among these are:
The International Society of Arboriculture, in Pruning Mature Trees: “Pruning should always 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…Removal of foliage through pruning can reduce growth and stored energy reserves. Heavy pruning can be a significant health stress for the tree…Mature trees should require little routine pruning.”
According to the National Arborists Association, “Topping…is a poor arboricultural practice and should never be used for healthy tree maintenance. Topping destroys branch structure, provides multiple entry points for wood decay organisms, and can turn your tree into a hazard, creating a liability for which you could be held responsible”.
In 2000’s An Illustrated Guide to Pruning, Dr. Edwin Gilman said, “Never top a tree. Instead, prune it to retain its natural shape…Trees should not be topped…Unfortunately, the trunk or large-diameter branches are sometimes headed to indiscriminate lengths in order to bring a large tree to a desired size. This…often causes decay and cracks in the cut branch stubs and trunk, depletes energy reserves, causes sunscald on the trunk and branches, weakens roots, destroys the tree architecture and structure, causes vigorous sprouting (sometimes—ed.), attracts boring insects, and wastes energy, because the removed branches have to be disposed of.”
In 1986’s A New Tree Biology Dr. Alex Shigo said, “Topping is also a major starting point for hazard trees. Malpractice suits may be in the near future for people who continue to top trees.”
In 1972’s The Pruning of Trees, Shrubs and Conifers, Mr. George E. Brown said, “too many of our present-day problems with trees are a direct result of this practice.”
From 1998-2000, the North Carolina Urban Forest Council posted notices in the Yellow Pages telephone directory under “Tree Service” warning consumers of the dangers of tree topping. Their Tree Topping Hurts! Information Sheet is the next page in this appendix.
Virginia Cooperative Extension’s Publication 430-458, Stop Topping Trees! is next.
The ISA brochures “Pruning Mature Trees” and “Why Topping Hurts a Tree” will be the final four pages in this appendix.
Many more citations could be made on this topic; these are just some of them. Virtually every state in the union has had an anti-tree-topping campaign underway.
