On a plot of land next to Tucson Electric Power’s H. Wilson Sundt Generating Station, green-waste compost from tree trimmings forms neat dark-brown rows.
The mulch — carefully chipped and composted with bacteria — is destined for the 70-acre Civano Nursery farm in Sahuarita, where it will help grow trees, shrubs and perennials that will be planted throughout Pima County.
TEP and Civano Nursery have worked together for nearly 10 years to recycle green waste clipped from around power lines. The partnership each year keeps about 30,000 cubic yards of tree branches, leaves and other waste from local landfills. The companies, in turn, donate mulch and trees to charities, schools and hospitals — benefiting the Tucson community.
“I tip my hat to Tucson Electric Power. TEP is a good community steward,” said Les Shipley, who founded Civano Nursery in the late 1990s and owns it with his three sons, Chris, Nick and Alex. “Instead of discarding this green waste, we are grinding it, composting it, shipping it down to our nursery and growing more trees.”
The TEP-Civano Nursery relationship is unique, said TEP’s Harold Hummer, who initiated the partnership in 2004. TEP is the only utility in the nation to have a successful, robust composting program, he said.
“Other utilities will have their solar fields and they’ll have their wind generators, but none of them do this,” Hummer said. “This is a national treasure. There’s nothing like it in the country.”
Hummer spotted Civano Nursery while driving down the Old Nogales Highway in June 2004. At the time, TEP was looking for a company to recycle its green waste, which was gathering in heaps in a corner of its Irvington campus.
Hummer stopped into the nursery, met Alex and Les Shipley, and shortly thereafter, the partnership was formed. Les Shipley knew nothing about composting at the time. “I read every book on composting that I possibly could,” he said. “It’s taken many years to perfect the process, but we did it, and now we have a product that’s one of the best in the industry.”
Green waste is brought to the mulch yard by Asplundh Tree Expert Co., which cuts it from around power lines throughout the greater Tucson area.
First, the clippings go through a grinder and are mixed with water and a bacteria inoculant. After a second grinding, the material is shaped into long rows, where the composting process is helped along with a special machine that keeps it aerated and moist. The process takes about six weeks to complete.
About 12,000 cubic yards of the finished mulch is shipped to Civano Nursery annually. With it, Civano grows close to a half-million trees, shrubs and perennials each year. About 95 percent of the plants grown at Civano Nursery are planted in Pima County. The nursery supplies plants to 300 to 400 local landscapers.
This past year, Civano Nursery invested about $400,000 in new machinery that speeds up the green-waste grinding. “It’s important for us to run an efficient and safe yard,” Shipley said. The partnership also promotes efficiency at TEP because the company doesn’t have to bring green waste to the landfill, a wasteful and time-consuming process.
“There are no better composters in the Southwest. Les Shipley has done us proud,” said Hummer, who plans to retire this year after 47 years with TEP. “When I leave the company, this is something I will take pride in accomplishing. This will be my legacy.”