Planting Shade Trees to Save Energy:
Designing Community Tree Planting Programs for Energy Conservation
Energy savings can grow in your yard! A report by Western Resource Advocates explores the substantial energy savings that can be reaped, and the increased quality of life obtained, by planting shade trees to shelter houses from summer heat. Through coordinated urban treeplanting programs, electrical utilities can benefit from substantial reductions in electricity demand, especially from mid-day peak loads. This report demonstrates that tree planting can be a very viable tool for reducing electricity demand.
The report, "Phoenix Green: Designing a Community Tree Planting Program for Phoenix, Arizona" lays out how southwestern cities can design a tree planting program that can effectively cut domestic and industrial cooling costs. The benefits are extensive and the costs reasonable to implement such a plan.
As unshaded and paved surfaces proliferate in fast growing southwestern cities, a phenomenon called the "urban heat island effect" is creating climates in cities that are even hotter than the surrounding deserts. Trees are an efficient method of mitigating the urban heating effect. At present, Phoenix has less than an estimated 13% vegetative coverage of any type, when 25% coverage of trees is deemed healthy for a southwestern city. Among the benefits of tree planting are:
- Estimated electricty savings per year per mature tree shading sun-struck side of house = 214 kWh
- 3 mature tress would reduce a house’s electricity consumption by about 4.6% per year
- For each 10,000 shade trees planted, CO2 emissions from power plants would decline by 15,000 metric tons over a 30 year period
- Shade trees are cost effective energy efficiency measures (costs of shade tree program are less than utility costs for generating electricity)
Water is always a concern in the desert southwest. For a tree planting program to be sustainable, a variety of desert-adapted and drought-tolerant tree species will be needed provide a sufficient canopy with minimal water consumption. The "Phoenix Green" report specifies a number of appropriate species including:
- Velvet mesquite
- Honey mesquite
- Chilean mesquite
- Desert ironwood
- Sweet acacia
- Blue palo verde
- Foothills palo verde
- Desert willow
- Texas ebony
- Feather tree
Tree planting is being recognized as an essential part of increasing the livability of all major cities. There are many successful tree planting programs in that can serve as templates for instituting city-wide tree planting programs. A few of these are:
- City of Tucson
- Tree People (Los Angeles)
- Trees for Houston
- Tree Folks (Austin, TX)
- Sacramento Tree Foundation
- Million Trees NYC
- Chicago Trees Initiative
The City of Phoenix has developed a master plan for tree planting. Calling trees a "solution multiplier" for all the various benefits received from a healthy urban tree canopy, Phoenix now considers trees to be an essential part of the city's infrasrtucture that must be developed and maintained. Read the Master Plan here.
Read the the Phoenix Green report here or view the powerpoint presentation being used to advocate for a tree planting program in Phoenix.
Other reports on the effectiveness of shade trees on energy savings: