While most components of Utility Vegetation Management (UVM) programs are looking up, PG&E's Vegetation Control (VC) program must look both up and down to manage fire hazards and comply with the law. California Public Resource Code (PRC) 4292 requires PG&E and the state's other public utilities to clear a fire break at the base of certain poles and towers. These poles are termed “subject” poles.

PRC 4292 mandates a cylindrical firebreak of at least a 10-ft radius by an 8-ft height around the perimeter of subject poles and towers in certain wild land areas. The law identifies eight pieces of electrical equipment that can expel hot material during normal or expected operation, making it a subject pole. These include universal and open link fuses, transmission air switches and lightning arresters. Out of PG&E's 2.3 million poles and towers, 120,000 are subject poles. These poles are identified by a unique six-digit metal tag that is used to reference information stored in a database.

California's climate presents special challenges. The state has enough precipitation in the winter to grow the world's tallest trees and support the most productive agriculture. However, when the rain ends in April, much of California faces six months without a single measurable drop of precipitation. To assure the 10-ft by 8-ft cylinder remains free of flammable material in this environment, PG&E manages for bare earth. By managing for the exclusion of plant growth, if any vegetation does grow, the amount should be so small that any fire will not be able to spread outside the cylinder.

PG&E uses two methods to achieve bare earth: chemical application and manual clearing. Where chemical application is not appropriate due to environmental concerns or the customer refusing to allow manual clearing, customers may sign a document agreeing to maintain the vegetation themselves in a fire-safe condition. We use two companies to create the firebreak and a third company to audit the completed work to provide continual feedback of work quality and level of compliance.

PG&E takes its fire-protection responsibility seriously. The VC program originated in 1966 and was centralized in 1997 under one program manager. Challenges remain due to annual weather patterns, customer concerns, expanding environmental laws and work force stability, but the program continues to focus on bare ground as being the best ground to prevent fires.