Warm Cows & Cool Breezes
Trees are a natural choice for moderating the extremes of our environment. They shade our homes and playgrounds, block cold winds, filter dust and pollutants from the air and make our cities nicer places to live. Trees have been called a low-tech solution to a high-tech problem. The high-tech problem is how to reduce our nation's growing demand for energy. Americans use more and pay less for energy than any other country in the world. The simple act of planting a tree can help reduce our energy demand.
Trees can save energy in several ways: through shade, reducing the need for air conditioning; as a windbreak, lowering heating costs, and by serving as a renewable source of fuel. Foresters can document energy savings of 10 to 40 percent in homes with strategically placed trees. Whether you live in the city or on a farm, planting a few well-placed trees can reduce your energy bill.
Keeping the Cows Warm
Windbreaks usually come to mind when someone mentions planting trees for energy conservation. Landowners have planted windbreaks for years to protect homes and farmsteads from winter winds in the Great Plains and Upper Midwest. Windbreaks also protect livestock, provide wildlife habitat, shelter crop fields and screen feedlots and traffic.
A 35' windbreak will slow 35 mph open wind speeds to 10 mph at 100' and 15 mph at 200'. Buildings should be no closer than 100' to windbreak.
Trees make effective windbreaks. Their leaves and branches absorb some of the wind's energy and deflect the wind up and over a protected area. This reduces the wind velocity or wind chill effect on the downwind-or leeward-side of the windbreak. The trees' height, density and orientation determine the effectiveness of a windbreak.
Windbreak height is the most important factor determining the downwind area protected by the windbreak. On the windward side of a windbreak, wind speeds are reduced upwind for a distance of two to three times the height of the windbreak. On the leeward side (the side away from the wind), the wind speed is reduced as far as 20 times the height. For example, if the tallest trees in a windbreak are 50 feet, wind speeds are reduced up to 150 feet on the windward side and 1000 feet on the leeward side.
Windbreak density is the solid portion of the