As one of the most populated countries in the world,environmental and ecological challenges associated with the rapid urbanization and booming economic development in China during the past decades have drawn unprecedented enthusiastic efforts to establish,maintain,manage urban trees and forest across the cities for the past 15 years driven by "Urban Forest City Campaign" initiated since 2004.It was estimated by the State Forestry Administration that each city planted 13,300ha trees annually for 180 cities joining the campaign.