Windbreaks
By Martin Shervey
Windbreaks Uses
Windbreaks create microclimates that can decrease the cost of heating in the winter on the leeward side of the windbreak. The savings can be 20 to 40 percent reduction in energy costs during the winter months.
They also increase the humidity in the summer, and allow other less hardy plants to grow. The relative humidity in sheltered areas can be 2 to 4 percent higher that in open areas. Higher humidity decreases the amount of water plants need, allowing garden plants to grow better with higher yields. The lower wind speed also reduces damage to plants and even increases bee activity.
The windbreaks can also be used to create natural snow fences that will reduce the drifting of snow in areas that receive large amounts of snow.
Wildlife habitats are a beneficial effect that windbreaks create. With a little more effort, windbreaks can be designed to attract the wildlife of your liking. This can provide entertainment for you family as well as help in educating children. This will also reduce the number of pest insects by attracting insect eaters.
Windbreak Design
When designing a windbreak, you need to take into consideration: the type and size of the trees used, what area you want sheltered most, and where and how to plant the windbreak.
The first thing you should know when you begin to design a windbreak is what is H. H is the height of the highest row of trees in the windbreak. The following graph shows how much wind speed is reduced by windbreaks and how far, on the leeward side.
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Open Wind Speed
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Leeward Wind Speed
|
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| mph | 5H | 10H | 15H |
| 20 | 5 to 10 | 10 to 14 | 14 to 16 |
| 40 | 10 to 20 | 20 to 28 | 28 to 32 |
From Ohio State University
The number of rows you have in your windbreak is also very important. You
should have a three-row windbreak to be most effective, but a five row can
be even better. The larger trees should be placed on the inside row with the
smaller trees on the outside rows.
The best types of trees you should us in you windbreak are evergreens, such as Norway spruce, Austrian Pine, etc. Broadleaf trees can be used also but they will not provide as much protection in the winter months. The type of trees you have to choose from becomes more complex when you are also developing a wildlife habitat.
You should plant your windbreak 100 feet beyond the area you want to protect. For maximum efficiency, the length of the windbreak should exceed the height by at least 10 times. The windbreak should also be planted at a right angle to be most effective. This can be demonstrated in the picture below.
It can take 20 years for your windbreak to fully develop but it can last for many more years and also increase the value of your property. There is also very little maintenance once your windbreak develops.
Sources
http://ohioline.osu.edu/for-fact/002-3.html
http://www.msue.msu.edu/msue/imp/mod03/03900114.html
http://muextension.missouri.edu/xplor/agguides/hort/g06910.htm
http://www.unl.edu/nac/aug94/snowfences/snowfence.html
http://www.unl.edu/nac/brochures/ec1771/index.html
http://www.unl.edu/nac/brochures/ec1763/index.html
http://www.ianr.unl.edu/pubs/forestry/ec1767.htm