by Tom Webber…
It sure gets hot in the summer! Is it global climate change, or has it always been like this? Hard to say, but one thing that is certain is that shade trees can have a big impact on the insolation that turns buildings into ovens. Some studies claim that mature shade trees strategically planted on the south, southwest, and west sides of buildings (in the (Northern Hemisphere) can reduce summer air conditioning load by up to 40%. (http://actrees.org/site/stories/shadetree_mechanics.php?tag=news) This demand side management represents a huge savings in terms of energy use and greenhouse gas emissions associated with this electricity generation, not to mention monetary savings to the consumer. The savings are particularly important because peak power is the most expensive kind, and reducing the peak has a number of benefits, not least of which is to eliminate the need for new power plants. Cutting the chilling winter winds, these same trees can reduce heating bills and associated energy and environmental costs.
The shade trees have a number of other benefits, not least of which is the natural beauty they bring to the landscape. The trees also bring other benefits because their respiration provides natural cooling outside, they bring groundwater to the surface, trees act as windbreaks, the roots control local erosion, and more. Of course, during the winter, the deciduous trees lose their leaves to allow the sun’s rays to warm the same structures they protect from the blazing summer sun.
Formal program to encourage shade trees exist in a number of places. For example, The Sacramento Tree Foundation in California is a model program that has been in place for about 27 years, and has had phenomenal success building an urban forest in this state’s capitol city. This nonprofit formed a valuable partnership with the local municipal electric utility, Sacramento Municipal Utility District (SMUD), and together they have planted or caused to be planted more than 1.25 million trees. Thanks to SMUD, many of these trees were provided free. Not resting on their laurels, Sactrees plans to plant 5 million additional trees by 2025. There is an excellent website at www.sactrees.com, which includes a great deal of valuable information, including instructional videos on exactly how to plant trees.
A number of other formal shade tree programs are available. Trees for a Green LA is another shade tree program sponsored by a municipal utility, in this case the LA Department of Water & Power. This program tries to reduce the Urban Heat Island Effect, which is huge there given the number size of the metropolis. Again, the utility provides trees for free, which allow it to reduce the need for new power plants, or for power purchases during the peak summer heat. While it is debateable how much the trees increase property values, they certain make the quality of life better for all residents and workers. See their website to learn more about this program. (http://www.ladwp.com/ladwp/cms/ladwp000744.jsp).
Every day is a good day to plant a tree, but shade tree planting days are fantastic. While native and locally-adapted trees are the best choices for a particular climate, there are plenty of excellent more exotic species that will work as well. The local Cooperative Extension office is a terrific resource where people can get advice on appropriate trees for their area. Additionally, local tree nurseries, arborists, or garden stores, plus books and the internet are all great sources of information. If this article inspires you to plant shade trees, please visit the 4-H Million Trees Project (www.4hmilliontrees.org), and register these trees toward the project goal.
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