Blocking Highway Noise with Evergreens
Q. When I am out in the yard, I can hear the traffic from Highway 16, foghorns, sirens, and trains. The highway noises bother me the most because they do not seem to be constant or short-lived, the trucks and motorcycles seem to be the worst offenders. Is there anything that I can plant to deaden the sound and turn the yard into a peaceful, quiet retreat? The highway must be at least six blocks away. Thanks, Karen Osterman - Tacoma, WA
A. Well if you can’t see the highway from your home then I am afraid a hedge of dense evergreens like arborvitae won’t do the trick. The major benefit of these kinds of screens is more psychological. I say this because studies have shown that shrubs and other landscape modifications reduce traffic noise only by a few decibels and usually only the higher frequencies. (e.g. Traffic Noise Attenuation as a Function of Ground and Vegetation by Rudoff Hendricks, 1995). Sometimes when vegetation is removed near highways there are more complaints about noise. This is because the noise source is visible and the traffic sound changes in quality (the higher frequencies make the sounds more noticeable). Sometimes white noise that can be produced by a landscape feature like a water fountain can help mask traffic sounds (psychoacoustic) so that could be an option, but you still may notice loud bursts of sound.