Southern California Edison (SCE) has launched a pilot program aimed at improving the effectiveness of the utility’s ongoing walnut tree pruning efforts in the Central Valley.

If successful the pilot program would reduce the number of “toppings” completed by SCE of the region’s walnut trees, a major cash crop, near the utility’s transmission lines in or near the valley’s many orchards.

“We’re required to maintain a clearance between all of our high-voltage power lines and the trees,” said Jiggs Travis, a manager in SCE’s transmission and distribution business unit. “The 220,000-volt transmission lines are particularly critical since they provide so much power for the San Joaquin Valley and the rest of California. We want to do that as effectively as possible and at the same time, we want to do what’s best for these rapidly growing trees and the growers.”

Trees contacting utility transmission lines can cause major disruptions of electrical service. In 1996, for example, a tree contacting a sagging power line in the Pacific Northwest resulted in a massive, cascading power disruption that affected the western United States and parts of Mexico and Canada, knocking out power for millions.

Historically, in order to ensure reliable service and regulatory compliance, SCE personnel “topped” trees in the valley’s orchards at least twice a year, once during the winter dormant season and again in summer. SCE wants to ascertain if different prune cycles and other practices can control rapid regrowth. If the trials are successful, SCE will advise the growers of the benefits and institute changes in 2006.

On Oct. 20 in cooperation with the Tulare County Farm Bureau, SCE will host a workshop at the utility’s Agricultural Technology Application Center in Tulare, for walnut growers with orchards in SCE’s transmission corridors.

SCE urges anyone who sees a tree touching a power line to call the company as quickly as possible at (800) 655-4555. Anyone with questions about safe working clearances also can call that number.

SCE urges anyone working near power lines to exercise caution.

Only qualified line clearance tree trimmers are permitted to prune trees near power lines. All persons and equipment must maintain a minimum clearance of 17 feet from 220,000-volt conductors. Anyone working near overhead power lines or underground cables should:

— Assume all overhead lines are energized and dangerous.

— Never come in contact with a power line, directly or with any tool, or any part of a tree that is touching a power line.

— Never prune a tree that has a power line going through the canopy.

— Never cut a tree branch that could fall into power lines.

— Never use metallic tools or ladders when working near any power line.

— Never allow children to climb or play in any tree located near a power line.

— Always use care when you prune trees, and always be careful when moving machinery, tools or scaffolding near power lines.

— Always make a site survey for potential electrical hazards before beginning work, noting the placement of any overhead wires.

— Always use a safety “spotter” when moving overhead equipment.

— Use Underground Service Alert of Southern California — Dig Alert — to determine the placement of underground utilities such as electrical cables and gas lines. Call (800) 227-2600. Give at least two days’ notice before digging. Once identified, respect the identifying marks.

More information on safety is available at www.sce.com.