Windbreak Trees

Marianne C. Ophardt
Washington State University Cooperative Extension
Area Extension Agent  

It's been said that the Tri-Cities is a windy area. You betcha! You’ll get no argument from most area residents.  Wind erodes our soil and leads to nasty dust storms. Winter winds can increase a home's heating costs by 10 to 40 per cent.  Wind can also be just plain annoying.  You can't stop the wind, but you certainly can slow it down with strategically placed trees and shrubs ... windbreaks.

"A windbreak is a planting usually of both trees and shrubs that is designed and established to reduce the undesirable effects of strong winds," says Don Hanley, WSU Extension Forester.  Early settlers in the treeless areas of Washington and the rest of the Northwest needed trees to provide much needed shade and protection from the wind. Farmers planted fast-growing species of trees in a simple one to six row design. Single species of trees, such as eastern cottonwood, black locust, and Lombardy poplar, were planted fairly close together.  Not all these windbreaks were successful ... improper placement or poor selection of the tree species meant a failure to obtain the goal of diminishing the wind.

Things haven't changed much since the days of those early pioneers.  Farmers and homeowners are still planting windbreaks and still having limited success.  The main reason for the failure of windbreak plantings is that many are not given adequate care to get them off to a good start.  Plantings often succumb to a lack of water, competition from weeds, damage by livestock, mechanical injury from mowers and other equipment, and careless use of weed control chemicals. Windbreak plantings are just like any other landscape planting, the trees need care and attention to be able to live and grow.

While the pioneers had to guess what trees to use and where to plant them, scientific research has revealed the proper design, location, and types of trees that will provide the most effective windbreaks.

PLANNING

These are the things you should consider when planning your windbreak:

PLACEMENT

Our local prevailing winds tend to come from the west, but this may vary slightly depending on your situation and topography. A windbreak should be located so that it’s at a right angle to the prevailing winds, or as nearly as possible to a right angle. The closer it is to the right angle, the more effective it will be.

To be effective, the windbreak should be no more than 100 feet from the house.  At this distance, trees 35 or more feet tall break and lift the wind currents over the top of the home,  You can place the windbreak closer but make sure the trees don’t shade the house. 

The windbreak should also extend fifty feet beyond the length of the house and the area you want protected.  If you must have gaps in your windbreak rows to accommodate irrigation ditches, paths, driveways, etc., try to make the crossings at oblique angles so you don’t create your own sort of “wind tunnel.” 

NUMBER OF ROWS

Many people usually plant only one-row windbreaks. However, the more rows you plant, the more effective the windbreak.  If there is not enough room available for a full five rows, consider four or less rows. Be sure not to crowd the rows though.  Crowding slows growth and weakens the plants. Lower limbs of crowded trees tend to die out due to heavy shade.  Trees should be staggered between rows.

If there is only room for four rows, the best protection is achieved with a row of dense shrubs, a row of medium evergreens, a row of tall evergreens, and a row of medium evergreens.  With three rows you’ll get the maximum protection with single rows of a dense shrub, a tall evergreen, and a medium evergreen.  With two rows, you’ll want to use a medium evergreen and a tall evergreen. If you only have room for one row ... use a tall evergreen, such as arborvitae.

SPACING

The spacing between rowsc should be sixteen feet.  The spacing between plants in the rows should be: