How do trees reduce noise pollution?

Trees benefit us in even more ways than you knew.

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Mon, Sep 15 2008 at 1:03 PM

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Forests & Trees, Natural Resources, Nature, Pollution

Q. I know trees are helpful for CO2 exchange and provide shade for cooling, but lately I heard about trees being useful to reduce noise and sound pollution. How does this work? - Barbara S. Alton, IL

A. What's not to love about trees? Not only do they absorb carbon dioxide, provide shade, prevent erosion and look darn pretty, they can also help muffle the sound of your neighbor's weed whacker. Think of them as big, leafy, air-purifying, oxygen-producing, white noise machines.

"It's the sound produced by the wind passing through the leaves that really helps muffle noise," explains Robert Smith, a staff arborist for the Arbor Day Foundation. As a bonus, trees also provide habitat for birds, whose twitterings add to the pleasant background sounds. A properly-designed buffer of trees and shrubs can reduce noise by about five to ten decibels -- or about 50 percent as perceived by the human ear, according to the USDA National Agroforestry Center.

For maximum effect, experts suggest planting a variety of both hedges or shrubs and taller trees to create a wall of foliage from the ground up. You'll probably want to do a little research to pick the best species for your area, sunlight and soil conditions, but in general, cottonwoods, poplar and aspen trees are especially good at noise reduction because their leaf-shapes produce a good, strong rustling sound. The Arbor Day Foundation also offers plenty of resources to help people chose the right trees, like the online Tree Wizard, which gives suggestions based on your region and needs.

Story by Sarah Schmidt. This article originally appeared in Plenty in September 2008.

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