Can planting trees actually save you money? Not just you, but the entire United States according to a report that I read recently at a fascinating web site called Pioneer Thinking. According to the report prepared by the National Academy of Sciences (NAS), urban America has 100 million potential tree spaces (i.e., spaces where trees could be planted). NAS further estimates that filling these spaces with trees and lightening the color of dark, urban surfaces would result in annual energy savings of 50 billion kilowatt-hours -- 25% of the 200 billion kilowatt-hours consumed every year by air conditioners in the United States.
This would reduce electric power plant emissions of carbon dioxide by 35 million tons (32 million metric tons) annually and save users of utility-supplied electricity $3.5 billion each year (assuming an average of $0.07 per kilowatt-hour).
You can read more about the NAS report and find some helpful ideas on energy-efficient landscaping at http://pioneerthinking.com/gardening/landscape/ or you can click on a direct link by going to my web site www.landsteward.org and find this column under "The Plant Man".
For most of us, it's hard to imagine vast sums such as $3.5 billion. We're more interested in what it means to us personally! How does an extra $250.00 sound? Consider this: Carefully positioned trees can save up to 25% of a household's energy consumption for heating and cooling, according to computer models created by the U.S. Department of Energy. They estimate that the proper placement of only three trees would save an average household between $100 and $250 in energy costs annually. With summer just around the corner, the idea of a pleasant spot beneath a cool shade tree is very appealing.
Trees do more than simply keep the sunlight off you. There's something known as evapotranspiration taking place. That's the process by which a plant actively moves and releases water vapor. The air temperature can be as much a 25 degrees F cooler beneath a tree than on a patch of nearby blacktop.
You don't have to stand directly under a tree to reap the benefits, either. Studies by the Lawrence Berkeley Laboratory found summer daytime air temperatures to be 3 degrees F to 6 degrees F cooler in tree-shaded neighborhoods than in treeless areas. The Pioneer Thinking web site states that a well-planned landscape can reduce an unshaded home's summer air-conditioning costs by 15% to 50%.
One Pennsylvania study reported air-conditioning savings of as much as 75% for small mobile homes. You might want to consider one of my favorites, a Willow hybrid known as "Red Baron", so-called because of its red-tinged branches. It grows fast, too: about six feet per year under normal conditions. Another good choice could be the Sugar Maple (Acer saccharum). It's a very attractive shade tree with beautiful fall color. You can often see Sugar Maples in parks or on golf courses, too.
Remember to plant larger trees no closer than twenty feet from the house. Smaller trees, such as dogwoods, can be planted about fifteen feet from the house. Trees planted on the south or southwest side of the house will be the most effective in blocking the heat and sunlight from mid-day to late afternoon. When planting any type of tree, be aware of the location of sewer and water lines underground, as tree roots could cause serious damage in the future.
And remember to look up and be sure you're not planting your trees directly under telephone or electric power cables! Here's a useful tip: deciduous trees are preferable to evergreens when it comes increasing the energy efficiency of your home. Why? Because the leafy canopy shades your home in the heat of the summer, but when the leaves fall, warming sunlight is able to reach your walls and windows unhindered.
You might be considering adding an awning to provide shade over a large picture window or French doors. An attractive, living alternative would be to build an arbor along the south side of your home. Fast-growing plants such as Wisteria or Honeysuckle can be trained up the sides and along the top. You could also try Virginia Creeper or Climbing Hydrangea on your arbor for your living ‘awning'.
So you see, some thoughtful additions to your landscaping can add beauty and save you some of your hard-earned money this summer. Not just the summer, either. In a future column I'll talk about how landscaping can save you money in the winter, too.