No one would argue that managing vegetation near transmission lines is not an important factor in making the electricity grid less vulnerable to blackouts ["Utilities Uneven in Managing Vegetation," Business, Sept. 9]. Unfortunately, most utility companies fail to train their technicians in the proper way to prune trees. As a result, the butchery that is often inflicted on trees along power lines fuels the indignation of those who value the trees for their beauty, contribution to air quality and protection of wildlife.

Apart from that, the proper care and management of trees is consistent with good science and sound economics. A tree that is trimmed the right way lives considerably longer than one that has been hacked. The most common pruning errors are:

* Lopping off a branch halfway to the trunk.

* Cutting a branch flush with the bark, instead of making the cut just outside the branch's "collar" and allowing the tree to close the wound.

* Topping trees too aggressively. A badly hacked tree invites disease and decay, which can result in its weakening and finally the premature loss of the plant from a hurricane or an intense rainstorm. And we know the costs, financial and otherwise, when lines come down.

JAMES CASSELL

Silver Spring