This same tree releases enough oxygen to support two human beings. Associated with this savings is a projected reduction of nine million tons per year of carbon dioxide emissions from power plants. Trees play a critical role in reducing air pollution in urban environments. David J. Nowak and E. Gregory McPherson, United States Forests Service Northeastern Forest Experiment Station, 1993. Texas Parks and Wildlife .
Trees create a much more livable environment.
Fox, Tom. 1990. The Neighborhood Open Space Coalition, New York, New York. When Cambridge tax assessors judge streets from 'excellent' to 'poor', street trees rank as their number-one priority in a rating a street 'excellent'. Brabrec, Elizabeth. 1992. Trees Make Sense.