Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: THURSDAY, October 27, 1994 TAG: 9410270052
SECTION: CURRENT PAGE: NRV10 EDITION: NEW RIVER VALLEY
SOURCE: JOE HUNNINGS
DATELINE: LENGTH: Medium
Winter Savings
One of the most sensible and attractive plantings to conserve energy is the windbreak. If your house is located where it is exposed to strong winds, windbreaks will be particularly effective.
The location of a windbreak is essential to its ability to shelter the house and cut fuel consumption. Since prevailing winter winds come from the north and west in most parts of the U.S., windbreaks are usually most effective on these sides of a house. Generally, savings from windbreaks increase as the protected perimeter of a house increases. Yet, only a few well- placed conifers will make a difference if your house is currently exposed.
We suggest that, where possible, windbreaks on the east or west be planted about 50 feet from a house. On the north side of your home, closer windbreaks will probably be more efficient. If local wind conditions warrant placement of windbreaks on the south side of a house, they must be farther from the house, to prevent winter shading.
Any conifer will provide effective wind protection, but in general, choose fast-growing, visually dense species with stiff branches. (Of course, you must first check which species grow best in your area.) Norway, white, and Colorado blue spruce are among the best windbreak trees; blue spruce usually provides the most protection, but is slower-growing than the others. Whichever species you choose, a fast-growing variety or cultivar will begin saving fuel costs more quickly.
Although single-row conifer windbreaks are quite suitable, the effectiveness of a windbreak generally increases with each added row, up to about five rows. However, with dense trees such as spruce, one or two rows is probably the most cost-effective windbreak.
The spacing of trees within a windbreak depends in part upon the species used. For narrow windbreaks, pine and spruce should be placed about six feet apart in the rows. Cedar and arborvitae should be about three or four feet apart. The rows themselves should be roughly 10 to 12 feet apart. Trees in the rows should be staggered in relation to the trees in adjacent rows.
A landscape plan for a half-acre home site with prevailing winter winds from the northwest and summer breezes from a southerly direction in a temperate portion of the country would incorporate coniferous windbreaks to protect the directions where the strongest winter winds come from and trees on the east and west sides to provide summer shade.
The year-round effect of foundation plantings seems never to have been measured, but the authors would expect them to be energy savers if they do not shade windows in winter.
One very important note: Don't prune the lower branches of windbreak trees. Trees so pruned can actually increase wind speed near the ground rather than reduce it. Another caution: a dense, single-row windbreak can cause nuisance snowdrifts if it is just upwind of a driveway or sidewalk.
It Pays to Save
The landscape around your home will serve you better, and in more ways, if you carefully plan and maintain your trees and shrubs. Landscaping for energy savings combines well with other benefits: a windbreak also provides privacy; shade trees beautify your yard and provide a habitat for local wildlife, as well as protecting you from sun and wind during outdoor activities. And, of course, trees increase the value of your property. The free bonus is the enhancement of your surroundings with soothing but vibrant green atmosphere.
Reprinted with permission of the Urban Forestry Program of the American Forestry Association.
Joe Hunnings is the Virginia Cooperative Extension agent for agriculture in the Montgomery County Extension Office in Christiansburg. If you have questions, call him at 382-5790.
by CNB