Hall and Tamer Ucar, a research associate at Ohio State, reviewed all previous windbreak research in scientific journals. They worked with Bruce Wight and Roel Vinning, both scientists with the United States Department of Agriculture's Natural Resources Conservation Service (USDA-NRCS).
The researchers discovered that none of the dozens of articles compared the efficiency with which different windbreak plants capture sprays. To gather some comparative data, Ucar built a windtunnel at Ohio State's Laboratory for Pest Control Application Technology in Wooster, Ohio, and hung branches from different plants inside.
He sprayed them with dye at windspeeds ranging from 1.5 to 3.5 meters per second, and measured the amount of dye captured. Evergreens -- plants such as pine trees which sprout cones and needles -- collected two to four times more dye than broadleaf plants, such as maple trees, which produce wide, flat leaves.
Hall said that evergreen needles offer a larger surface area
for collecting sprays, as well as an aerodynamic shape. As
air swirls around the needles, more droplets stick to these
surfaces than if the air were gliding over the smooth su
Contact: Franklin R. Hall
Ohio State University