It found that tree plantings increased the value of property by9%, adding, on average, a $3,400 premium to housing prices.Furthermore, there is a 64% rise in property values for neighborsof vacant lots that have been "cleaned and greened," which amountsto an average increase of $24,000.

For the first time, a study utilized new technology, includingthe satellite Geographic Information System, spatial regressionmodels, and econometrics, to measure the steady impact of greening,according to Susan M. Wachter, an author of the study and professorof real estate, finance and city planning at Wharton. "Philadelphiais at the forefront of using place-based policies to transformcities from decline to vibrant health," she says.

J. Blaine Bonham, EVP of the state horticultural society, says,"We were always convinced that greening has a tremendously positiveimpact on communities. The success of our Philadelphia Greenprogram has demonstrated this. The Wharton findings begin tovalidate the true impact in dollars and cents."