For sections of distribution and transmission lines that traverse long section of wooded or unmaintained areas, the previously described pruning methods are impractical in most cases due to difficult terrain, density of vegetation along the right-of-way corridor, and access issues.
Therefore, mechanical means such as boom-tip trimmers, forestry mowers, and sometimes rotor blade aircraft are implemented along with conventional methods such as hand cutting, and climbing in order to maintain line clearance in a safe and cost-efficient manner. (Figures 6 & 7)
Utilizing this method of maintenance, cuts are made outside of the branch collar, but as close to the trunk as possible while attempting to avoid any damage to the trunk. Even though this method is a departure from the directional pruning method used in landscape areas, it is still in line with ANSI 300 guidelines for pruning operations in Remote/Rural Environments.)
For additional information and resources concerning best practices for utility right-of-way management visit www.isa-arbor.com or www.gotouaa.org