Michigan
State University Extension
Home Maintenance And Repair
06/24/03
Energy Tips - Energy Conservation Landscaping-Winter Wind Protection
Protecting
your home from winter wind can help conserve energy by reducing the
rate of air exchange between the house and the outdoors. Reducing the
rate of air exchange will reduce the amount of fuel needed to warm the
house.
What is a windbreak?
The use of windbreaks--a way of planting trees generally consisting of
rows of evergreen trees--is one way to diminish the effects of winter
winds. Windbreaks do not actually divert all of the wind that reaches
them. Some wind penetrates the windbreak, but this is actually
beneficial and makes the windbreak more effective. When a windbreak is
100% effective--when no wind penetrates it--a great deal of turbulence
is created on the leeward side (back side) of the windbreak on windy
days.
A windbreak will reduce wind speed for a distance of as much as 30
times the height of the trees. The greatest benefit of the windbreak
occurs on the leeward side at a distance of about five times the height
of the windbreak. The windbreak needs to extend 50 feet beyond the
space that is to be protected. Such spacing, plus the space occupied by
the windbreak itself, may not be a problem for rural homes surrounded
by acres of property. But where space is more restricted, typically in
urban areas, it will be necessary to compromise Most homeowners will
not have sufficient property to create as large a windbreak as
described. If winter wind is a problem, even a single row of evergreens
on the north and west side of the property will provide some benefit.
One advantage of a smaller property is that fewer trees will be needed.
Consequently, the homeowner may be able to afford large plants that
will give an immediate benefit.
How do you design a windbreak?
The best windbreaks consist of multiple rows of trees planted on the
north and northwest side of the property. Evergreens are commonly used
because they retain their foliage throughout the year and are branched
out close to the ground. When the lower branches die, the addition of
shrubs or small trees will help fill in the lower part of the
windbreak. Avoid planting a windbreak on the south side of the home if
you are planning on the winter sun to help heat your home.
When planting a traditional windbreak, use at least two rows (three is
better) of evergreen trees. Stagger
the planting so that a tree in one row lines up with the space
between two trees in the adjacent row. Space the rows 12 to 20 feet
apart. A row of low shrubs on the windward side of the windbreak can
help reduce drifting snow by trapping it before it reaches the yard.
Planting a sizable windbreak can be a challenge. Many times the
windbreak is established using young trees or seedlings. Depending on
growing conditions, it can be difficult to ensure that the trees
survive their first year or two. It may be better to plant only the
number of trees that can be adequately watered and cared for the first
year. When these trees seem to be established, another row or
additional trees can be added. The biggest problem will probably be
extended dry weather during the summer. If possible, water the trees
regularly to get them established.
Tree Selection
Evergreen cultivars are available that offer property owners some
additional choices. Rather than plant spruce or pine trees that have
large mature heights and spreads, select other plants that have a
narrower, upright growth habit. These may be able to provide windbreak
benefits while taking up less space.
Another consideration for plant selection involves the choice of
species. It is not a good idea to plant rows of a single tree species.
They will all be susceptible to the same pest problems. If a fatal
problem infects one tree, it is likely to spread to all trees in the
windbreak. Mix up the species to prevent or reduce the risk of pests.
Deciduous trees can be included in the planting to provide an even
greater species diversity. Call your county Extension office for advice
on specific species.
In urban areas, evergreen plantings may be used for privacy as well as
a windbreak. Many times, evergreens are planted near roads or streets.
Keep in mind that most evergreens will be sensitive to salt spray
thrown up by automobiles when roads have been salted to melt snow.
White pine is particularly sensitive to salt spray.
Be sure to select trees that are adapted to your growing conditions.
Consider the soil type and whether the soil is particularly dry or wet.
Do not use salt sensitive trees near roadways. If possible, take a look
at mature windbreaks in your area to see which species seem to be
growing well and holding their form as they mature.
Other solutions
Where space is limited, it may be possible to get some relief from
winter wind by creating a dead air space next to the house. Tall,
columnar evergreens, or other shrubs, may be planted in groups or in a
row near the house to create the dead air space. Make sure the plants
are sufficiently far away from the house so that there is a space
between plants and house. The still air acts as insulation to reduce
the rate of air exchange between the house and the outdoors.
Plants can be used to control drifting snow. If the snowdrifts can be
induced to form where they do not block drives and sidewalks, energy
may be saved by reducing the need for snow removal. To be effective,
plants used to control snowdrifts cannot be located more than seven
times the height of the plants away from the road or drive.
For example, five-foot tall shrubs used to control drifting snow should
be planted no more than 35 feet from a driveway to provide maximum
benefit. Avoid planting shrubs along driveways since it will tend to
enhance snowdrift development where you least want it to occur. Shrubs
planted adjacent to driveways may also interfere with snow removal.
References
Energy Tips - Energy Conservation Landscaping-Winter Wind Protection,
Michigan State University
Extension E2800
Department of Energy. 1995. Landscaping for Energy Use. Consumer Energy
Information: EREC Fact Sheets. The Energy Efficiency and Renewable
Energy Clearinghouse. Merrifield, VA. Online. http://apps1.eere.energy.gov/consumer/your_home/landscaping/index.cfm/mytopic=11910.
[Downloaded July 20, 2001].
Keyser, Joseph M. Landscaping to Save Energy. Department of
Environmental Protection, Montgomery County, Maryland. Online.
http://www.montgomerycountymd.gov/content/dep/energy/pdf/Landscaping%20Winter.pdf,
.http://www.montgomerycountymd.gov/content/dep/greenman/shadyideas.pdf
[Downloaded July 20, 2001]
Mitchell, Paul J. Landscaping for Energy Conservation. OSU Extension
Facts, F-6417. Oklahoma Cooperative Extension Service, Oklahoma State
University.
North Carolina Solar Center. 1998. Energy-Saving Landscaping: For Your
Passive Solar Home. Online. http://www.ncsc.ncsu.edu/information_resources/factsheets/Energy_Landscape.pdf.
[Downloaded July 20, 2001].
Oberlin Municipal Light and Power. 2001. Energy Efficient Landscaping
Ideas. Online. http://www.omlps.org/Conservation/Landscaping.htm.[
Downloaded July 20, 2001].
Perry, Leonard P. 1997. Landscape to Conserve Energy. Ornamental
Horticulture Leaflet 47, University of Vermont Extension.
Starbuck, Christopher J. 2000. Landscape Plantings for Energy Savings.
Department of Horticulture, University of Missouri-Columbia. Online.
http://muextension.missouri.edu/xplor/agguides/hort/g06910.htm.
[Downloaded July 20, 2001]
Welch, William C. Landscaping for Energy Conservation. Texas
Agricultural Extension Service, Texas A&M University. Online.
http://aggie-horticulture.tamu.edu/extension/homelandscape/energy/energy.html.
[Downloaded July 19, 2001]
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