Horticulture and Forestry Advisory Board Agenda and Packet 2010 11 04

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http://www.denverpost.com/news/ci_16402656 r POST TIIE D ENV ER http://www.denverpost.com/fdcp?1287759146539 Print Powered By Page 1 of 2 denver and the west Deciduous trees have decidedly beneficial impact on air pollution By Bruce Finley The Denver Post Posted: 10/22/2010 01:00:00 AM MDT Updated: 10/22/2010 01:15:20 AM MDT y ��5 Officials in Denver embarked on a mission in 2006 to plant 1 million trees in the city by 2025. Trees, such as these in Civic Center, are helping scrub away some pollution a phenomenon underscored by scientific research published this week. (RJ Sangosti, The Denver Post) Trees may be pulling their weight. New research by government- backed scientists at the National Center for Atmospheric Research finds that deciduous vegetation absorbs one -t hird more air pollution than previously believed tens of millions of metric tons worldwide. The NCAR scientists, measuring air chemistry from Amazonia to Arizona, focused on some of the most pernicious pollutants the so- called volatile organic compounds that people emit from vehicles, lawnmowers and coal power plants. These are abundant pollutants that, when mixed with sunlight and nitrogen oxide, form the ozone in smog hanging over cities such as Denver. "Plant more trees, as long as they are the right trees," said NCAR physicist Thomas Karl, whose Boulder -based team's peer- reviewed report was published this week in the academic journal Science Express. "This will help reduce the levels of air toxics." The right trees include ash, apple, birch, hawthorn, hackberry, maple, pear and peach. Wrong: poplar, eucalyptus and oak, NCAR scientists say. These species, NCAR scientists say, emit more volatile organic compounds than they absorb. Scientists long have believed that plants absorb the greenhouse gas carbon dioxide. The new ForrnatC ynarr ics v 10/22/2010