The State of California Public Utilities Commission (CPUC) requires all utilities in the state to maintain vegetation clearance from their electric conductors and related equipment. The City of Palo Alto, as operator of its own electric utility, must be in compliance with CPUC rules. To comply with these rules and to deliver safe and reliable power to the residents and businesses of Palo Alto, the City has in place a Line Clearing Program.
The City has a project manager and inspector in the Urban Forestry Section of the Public Works Department that administer this program. The actual line-clearing work is conducted by a contractor that has expertise in trees and working around power lines. Generally, most public and private trees in the City are on a two-growing-season clearing cycle. Fast-growing trees are on a one-year pruning cycle, as are trees in the foothills. City staff pre-inspects for line clearance and then assigns needed work to the contractor. The work includes clearing electric conductors, poles, span and down guys, transformers, traffic signal lights and street lights. Certain poles in the foothills and bay lands require annual clearance around their bases for fire prevention.
Often, power line clearing can result in a less than desirable tree form. However, in order to provide safe, reliable power (especially during windy conditions) tree limbs need to be kept clear. Every effort is made to balance clearance needs with the health of the tree. In some cases, removal of the tree may be the best outcome.