Break that Wind
My friend Paul suggested writing an article on windbreaks. The basic premise for a windbreak is that a vertical element, whether trees, shrubs or fences, or any combination of those, placed perpendicular to the direction of the prevailing wind affects the movement of the air. How much of an area is impacted is determined by the height, width and composition of the barrier. If you are considering putting in a windbreak, determine if your goal is to reduce cold winter winds, direct cooling summer breezes or both. Another factor to consider is whether the windbreak’s purpose is to shelter a garden, the landscape or the house. Windbreaks not only provide wind protection, they also can reduce heating and cooling costs when installed properly.
While a windbreak can reduce wind speed for as much as 30 times the windbreak’s height, few residential lots need that kind of shelter. Planting a windbreak a distance from your home of two to five times the mature height of the trees will provide excellent protection. “The best windbreaks block wind close to the ground by using trees and shrubs that have low crowns” (www.energy.gov). Dense evergreen trees and shrubs are the most common type of windbreak, but in our high fire hazard area we have to be careful of planting too many evergreens, especially when they might create ladder fuels where flames can climb up from the lowest branches near the ground up into the canopy of the trees. “Trees, bushes, and shrubs are often planted together to block or impede wind from ground level to the treetops” (www.energy.gov). Combining plants, particularly evergreen trees, with walls, fences, or earth berms (raised areas of soil) can deflect or lift the wind over the home. Another advantage to a berm-type windbreak is as a sound barrier. Be aware that planting evergreens on the south side of a structure will prevent winter sunshine from warming the home.
According to http://www.arborday.org: “The down-wind side of the trees is where the most snow accumulates, so plant your windbreak a one or two tree-height distance from your rooftop and driveway if you can.”
Besides their use as wind directors, deflectors, shade or sound barriers, windbreaks serve as wildlife habitat, providing much-needed shelter for birds and other wildlife. Windbreaks are practical in many ways as well as being aesthetically appealing. I love the fact that our windbreak shields us from the street, providing privacy.
JoAnne Skelly is Associate Professor & Extension Educator, Emerita, University of Nevada Cooperative Extension. She can be reached at firstname.lastname@example.org.