Twelve thousand trees. That's how many trees it takes to create the 12,000 utility poles replaced each year by just one of the state'smajor utilities. The poles fall victim to many of the same agents of destruction that affect wooden structures of any kind -- fungal rots and termites. Until recently there was no reliable method of accurately determining which poles actually needed replacing. "Many of the existing techniques lacked sufficient sensitivity to detect all but advanced decay," says Frank Beall, director of the University of California's Forest Products Laboratory. Beall and a team of laboratory scientists, however, have developed a new process that will enable utility companies to fine-tune their utility pole replacement programs at a substantial savings to the industry. Each pole costs $2,000 to replace, so even a 1 percent reduction in removals would save a substantial amount of money. The new technique uses sound waves to analyze the integrity of each pole and has proven very accurate in research tests. Since the preservatives used in utility poles are also considered hazardous, there is an additional benefit for the environment by reducing the disposal problem.