A growing number of utilities in Southern California and across the country are turning to a decidedly low-tech way of pushing energy conservation: trees.
Power customers in Anaheim and Riverside, and soon in Los Angeles, can get shade trees, meant to cool houses naturally, through utility programs that offer free trees or rebates.
As California's summer heats up with an energy crisis hanging overhead, the number of requests for free shade trees in Anaheim was up 50% to 565 during May and June. Since its start in 1992, more than 16,000 trees have been planted through the city-owned utility, which offers customers up to three free 15-gallon trees, plus rebates of up to $20 for three more.
"Energy conservation is on the top of everyone's mind right now," said Melanie Nieman, spokeswoman for Anaheim Public Utilities.
In 1991, the American Public Power Assn. launched a nationwide Tree Power initiative to encourage utilities to plant trees in their communities to save energy and reduce air pollution.
Since then, 165 of the nation's more than 2,000 community-owned electric utilities have started their own shade-tree programs, and the number continues to grow.
Strategically planted shade trees can significantly reduce the energy required to cool a home, said Hashem Akbari, head of the Heat Island Group at Lawrence Berkeley National Laboratory.
His group conducted studies that found shade plus the cooling effect from evaporation by trees also reduces the air temperature around a home. The studies found summer daytime air temperatures to be 3 to 6 degrees cooler in tree-shaded neighborhoods than in treeless areas.
"In moderate climates, when the demand for summer cooling is very small, trees can potentially eliminate your need for cooling," Akbari said. "However, in inland areas where an extensive amount of cooling is required, strategically planted trees can save 10 to 15% of the summer cooling load, which would produce an annual savings of $30 to $50."
Kris and Mathew Barnett of Anaheim received two free trees through the utility's TreePower program in March--a pink orchid tree and an ornamental pear--which they planted in their frontyard to shade two bedroom windows of their 1950s ranch-style house. The utility offers 50 varieties of trees, which typically retail for $35 to $55.
"We're hoping they will add to the energy efficiency of the new air-conditioning system we put in," Kris Barnett said. "We live in an older house that's not very well-insulated, so we want to do whatever we can to improve energy efficiency."
Since starting its program two years ago, Riverside Public Utilities has offered customers rebates on shade trees--up to $25 per tree, with a limit of five trees per customer each year.
In September, the Inland Empire Utilities Agency in Fontana, working with school and civic groups, will launch its own program by donating trees for community plantings.
"The topic of the hour is how to reduce energy costs in cooling our buildings, but planting trees also will help to address improved air quality, address reducing global warming gases and contribute to water conservation," said Martha Davis, the utility's manager of strategic policy development.
Considered the largest mass tree-planting utility-funded program in the nation, Sacramento's Shade Tree program has given away more than 300,000 five-gallon trees to about 100,000 households since 1990.
With an annual budget of $1.5 million, it provides about 25,000 trees a year. Last year, nearly 10,000 people signed up.
And in October, the Los Angeles Department of Water and Power will launch its own ambitious tree giveaway program called Trees for a Green L.A.
Funded under the department's public benefits program, the $8-million, two-year pilot program will provide 200,000 free trees for planting near residences, public buildings, in public spaces and at new construction sites throughout the city. Residential customers can receive up to seven five-gallon saplings. As with other shade tree programs, homeowners will attend educational workshops offering advice on tree selection, planting and care.
"What justifies us giving the trees away is connecting it to a tangible benefit in terms of energy efficiency and air quality," said Angelina Galiteva, DWP director of strategic planning.
The trees ultimately will reduce air pollutants by thousands of tons, she said.
Trees for a Green L.A. comes on the heels of the DWP's Cool Schools program, which has provided 4,500 free trees for planting at more than 45 Los Angeles schools in the last two years. Plans call for doubling the numbers in the next two years.
Some of the programs deliver the trees; others expect customers to pick them up. Homeowners are responsible for planting the trees, but the utilities offer tips and sometimes inspections.
Ron Vanderhoff, nursery manager at Roger's Gardens in Corona del Mar, said it takes at least four years for a typical eight-foot sapling to grow enough to provide a significant amount of shade. Most trees mature in about 15 years, he said.
Eight years after receiving their first two free trees from the TreePower program, Gloria and Gabriel Criscuolo of Anaheim have finally started seeing some benefits.
Inspired by the results, the couple obtained two more trees two years ago.
"Now," Gloria Criscuolo said, "we're just waiting for the trees in the backyard to grow some more."