Growth Rate For Central Park Red Oaks 8X Those In Rural Areas; Heat Island Effect May Play Part
Red oak seedlings in Central Park grow up to eight times faster than their cousins cultivated outside the city, probably because of the urban “heat island” effect, Columbia University researchers report.
The researchers planted seedlings of the native red oak in the spring of 2007 and 2008 in four places: in northeastern Central Park, near 105th Street; in two forest plots in the suburban Hudson Valley; and near the city’s Ashokan Reservoir in the Catskill foothills about 100 miles north of Manhattan. By the end each of summer, the city trees had put on eight times more biomass than those raised outside the city, according to their study, published in the journal Tree Physiology.
“The seedlings grew much larger in the city, with decreasing growth as you get farther from the city,” said the study’s lead author, Stephanie Searle, who was a Columbia University undergraduate when the research began and is now a biofuels policy researcher at the International Council on Clean Transportation in Washington.
The researchers hypothesized that Manhattan’s warmer temperatures — up to eight degrees higher at nighttime than in rural surroundings — could be a primary reason for the Central Park oaks’ faster growth rates.
EDIT
http://green.blogs.nytimes.com/2012/04/25/on-an-urban-heat-island-zippy-red-oaks/