ABSTRACT
In a rapidly urbanizing world, cities have become main centres of demand for ecosystem services, and sources of environmental impacts. Analyses of urban ecosystem services also present some unique challenges and options when compared to rural areas. Also, in urban areas it is very clear that ecosystem services are generated by a tightly coupled social-ecological system, where the feedbacks between flows of services, values, institutions, management and practices are very evident. Food supply from urban agricultural land and gardens have played a critical role in the development of cities throughout history. Urban green infrastructure, especially trees, removes pollutants from the air and filters out gases and airborne particulates. Green infrastructure can enhance nutrient retention by adding coarse woody debris, constructing in-channel gravel beds and increasing the width of vegetation buffer zones and tree cover. Worldwide, city authorities are looking for innovative ways to maintain and increase urban green infrastructure and ecosystem services through urban planning.
