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| Tree Facts: In laboratory research, visual exposure to settings with trees has produced significant recovery from stress within five minutes, as indicated by changes in blood pressure and muscle tension (Ulrich, P.S. 1984. View through a window may influence recovery from surgery. Science, 224: 420-421)
Symptoms of children with Attention Deficit Disorder (ADD) are relieved after contact with nature. The greener the setting, the more the relief. By comparison, activities indoors such as watching TV, or outdoors in paved, non-green areas leave ADD children functioning worse (Taylor, Kuo, F.E., and Sullivan, W.C., 2001. Coping With ADD: The Surprising Connection to Green Play Settings, Environment and Behavior. Vol. 33 No. 1. 54-77.)
Researchers report that inner-city girls with greener and more natural views at home had greater self discipline. They were less impulsive and had better concentration. These traits led to better life decisions and better school performance (Taylor, F.A., Kuo, F.E., Sullivan, W.C., 2002. Views of Nature and Self-Discipline: Evidence from inner city children. Journal of Environmental Psychology, 22, 49-63.)
Poplar and cottonwood trees can breakdown carcinogenic groundwater contaminants such as trichloroethylene (TCE) and atrazine into harmless compounds. As a result, trees are now being planted at remediation sites across the county to help reduce pollutants while improving the environment (Black, H; 1995. Absorbing possibilities: Phytoremediation, Environmental Health Perspective, Volume 103, Number 12.)
(Environmental Protection Agency, 1996. Citizen\'s Guide to Phytoremediation. Office of Solid Waste and Emergency Response; EPA 542-F-96-014.)
A major study of Chicago estimated that trees in that city annually removed 15 metric tons of carbon monoxide, 84 tons of sulfur dioxide, 89 tons of nitrogen dioxide, 191 tons of ozone, and 212 tons of small particulates. The estimated value of this pollution removal was $1 million for trees in the city itself and $9.2 million for the entire Chicago area (Nowak, D.J., 1994. Air pollution removal by Chicago\'s urban forest. In: McPherson, E.G.; Nowak, D.J.; Rowntree, R.A. [compilers]. Chicago\'s urban forest ecosystem: results to the Chicago Urban Forest Climate Project. Gen. Tech. Rep. NE-186. Radnor, PA: U.S. Department of Agriculture, Forest Service, Northeastern Forest Experiment Station: 63-81.)
Trees, especially those with large leaf-surface areas, absorb and trap airborne dirt and chemical particles, such as nitrogen oxide, sulfur dioxide, carbon monoxide, and ozone. Trees also help by reducing wind speed so that heavy particles settle out
(Nowak, D.J., 1994. Air pollution removal by Chicago\'s urban forest. In: McPherson, E.G.; Nowak, D.J.; Rowntree, R.A. (compilers). Chicago\'s urban forest ecosystem: results to the Chicago Urban Forest Climate Project. Gen. Tech. Rep. NE-186. Radnor, PA: U.S. Department of Agriculture, Forest Service, Northeastern Forest Experiment Station: 63-81.)
(Harris, R.W. 1992. Arboriculture: integrated management of landscape trees, shrubs, and vines. Englewood Cliffs, NJ: Prentice Hall. 674 p.)
Trees can limit soil erosion by helping control storm-water flow. Fibrous root systems hold soil in place so that it is not washed away by rain or flowing water. Erosion can be especially severe at construction sites in urban areas. Research has found that while forested land can lose about 50 tons of soil per square mile per year, developing areas can lose 25,000 to 50,000 tons (Lull, H.W.; Sopper W.E. 1969. Hydrologic effects from urbanization on forested watersheds in the Northeast. U.S. Department of Agriculture, Forest Service, Research Paper NE-146:1-31.)
These facts can be found in the Treelink.org web site (http://www.treelink.org/linx/factoid.php)
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