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(For the week of September 29, 2008)
Landscaping to Conserve Energy
with James L. Cummins
Today's energy prices have everyone scrambling for ways to cut costs. One often overlooked way of reducing energy costs is through landscaping. It not only helps with your energy bills, it also enhances the overall beauty and value of your property.
Because plants transpire (release water vapor from leaves) during the day, they serve as an evaporative coolant. Therefore, trees, shrubs, ground covers and grasses affect solar radiation more than structural devices such as awnings. Shade trees significantly reduce air temperatures indoors and outdoors in the summer as trees intercept and absorb the sun’s heat while transpiring cooler temperatures into the air.
Before buying up every tree you can find, you should take a few things into consideration. First, you should spend some time outdoors. Pay attention to how the sun falls across your property at different times of the day. We all know that the sun rises in the east and sets in the west, but did you know that it rises more from the northeast during the summer solstice and the southeast during the winter solstice? So, keep this in mind as you decide how and what to plant for which season.
To provide morning shade in the summer, trees should be planted on the eastern and northeastern exposures of your home. For afternoon shade, trees placed on the western and northwestern exposures of your home are most effective. However, avoid placing trees too close to your home; planting trees a distance of 25 feet from the walls or roof line is usually adequate. Also, take precautions to plant away from power lines, underground sewer, water or utility lines and be sure to space trees properly according to their anticipated mature size.
Consider planting vines or shrubs on the east and west walls to increase heat absorption. Be careful to only grow vines directly on masonry brick or concrete walls or build a structure such as a simple trellis to grow indirectly on wooden sidings.
In most areas of Mississippi, cool summer breezes are provided by the Gulf from the south and southwest. Therefore, avoid dense plantings on the south and southwest sides of your property in order to take full advantage of these breezes.
Effective tree planting will allow the winter sun to warm the roof and walls of your house. An important consideration for energy conservation in the winter is the use of deciduous tree species. These trees lose their leaves in the winter and should be planted on the east and southeast sides of your home to allow the sun to help warm the house.
Cold winter winds typically prevail from the north and northwest. A screen planting of evergreen trees such as pine, magnolia, American holly and cedar along the north and northwest of your property will provide adequate wind protection so that your heater does not have to work as hard to heat your home.
In summary, remember these tips for placing trees for energy conservation: avoid planting trees too close to your home; avoid planting under power lines or over underground sewer, water or utility lines; space trees according to their anticipated mature size; and avoid using evergreen species on the south side of your home. Most importantly, be conscious of where the sun will be throughout the year and the effect this has on your home and plantings.
Remember also that this is only a general overview of how landscaping can help conserve energy. If you need help deciding what to plant and where, contact your local plant nursery. Shade trees beautify the landscape as well as protect your property from sun and wind damage. So, do yourself a favor and seriously consider landscaping to conserve energy.