Windbreaks obstruct and redirect the flow of wind. As
wind strikes an obstruction it can move over, around and through it.
The extent of protection on the leeward (downwind) side
is related to the height and length of the windbreak. An impenetrable
(solid) windbreak creates a strong vacuum on the leeward side which
reduces the protection provided. Windbreaks composed of living plants
allow some of the wind to pass through which makes them more effective.
The zone of protection for a living windbreak is
approximately twenty times its height. Maximum protection occurs in a
range of 6 to 8 times the height of the planting so a windbreak 25 feet
tall should be located 125 to 175 feet (no more than 300 feet) from the
Windbreaks should be at least three rows wide (5 rows
is better) to be the most effective. The tallest growing trees (preferably
evergreens) should be in the center rows, while the shorter trees and
shrubs are best placed in the outer rows on both sides.
Rows of trees should be spaced about 10 to 20 feet
apart, while each tree should be spaced between 8 and 18 feet apart within
the row, depending on the size of the tree.
Windbreaks should be planted at right angles to the
prevailing winds (usually westerly, therefore the wind-break
should run north and south).
Woody ornamentals planted as windbreaks should include
a mixture of deciduous and evergreen trees and shrubs. The following table
documents the height and spacing required of a variety of species:
The above list of plant species includes those most
commonly used in windbreaks. However, there are many other plants that
will also work on your site.
A few of the plants on this list have excellent
physical characteristics for use in windbreaks but have other problems
that should be considered.
Scots (Scotch) pines are plants
that tend to get disease and insect problems as they age. Young trees
will provide a good windbreak but, after about twenty or more years,
they are susceptible to needle cast diseases and may begin to decline.
Mixing species of plants and staggering rows in the windbreak will allow
for these problem trees to be removed later without leaving holes in the
Most of these plants and many others suitable for
windbreaks are available in garden centers, nurseries, mail order
nurseries, and from soil conservation districts.