Tree care professionals contracted by East Central Energy use 'directional' pruning techniques. These techniques were developed by the National Arborist Association and are published by the American National Standards Institute (ANSI). Directional pruning is the accepted industry standard endorsed and promoted by the National Arbor Day Foundation and the International Society of Arboriculture.


Directional pruning removes entire branches and limbs back to the main trunk of the tree, where trees normally shed them. By using this practice, future tree growth is directed away from power lines and weakly attached re-growth is minimized. Directional pruning takes advantage of strong points in the tree's structure. Branches growing away from electric lines or facilities with adequate line clearance are usually left undisturbed. Directional pruning does not harm the tree's natural defense systems and other natural processes that protect the tree from decay and aggressive re-sprouting. East Central Energy's contract tree crews use this procedure for pruning trees in yards.

Before branches growing near electric lines are removed, pruning crews evaluate a tree's structure and growth patterns. Crews also consider the tree species, growth rates common to Minnesota and Wisconsin, proximity to electric lines and the height and voltage of the lines.

Directionally pruned trees may appear misshapen. In the long run, however, such trees are less susceptible to pest and decay problems and less likely to drop branches and cause damage during storms. In fact, compared to other methods such as topping, stubbing or pollarding, directional pruning is better for the protection of the tree's health. Where severe pruning is necessary to obtain satisfactory clearance, the tree may be selected for removal.

See Tree Growth Study