It is generally accepted that the single largest cause of electric power outages occurs when trees, or portions of trees, grow or fall into overhead power lines1. Virtually every electric customer in the US and Canada has, at one time or another, experienced a sustained electric outage as a direct result of a tree and power line conflict. While this is a more common problem on distribution lines, transmission tree-related outages are also experienced on a regular basis.

While not as visible to the public as tree related outages, tree and power line conflicts have also caused significant wildland fires in both the US and Canada. Electric utility companies actively work to mitigate these threats. In fact, Utility Vegetation Management (UVM) programs represent one of the largest recurring maintenance expenses for electric utility companies in North America. Utilities and regulators generally agree that keeping trees and vegetation from conflicting with overhead conductors is a critical and expensive responsibility of all utility companies concerned about electric service reliability and fire mitigation...