As the world's population has grown it has become increasingly concentrated
             in large urban areas. The extent to which urbanization impacts the
             ecosystems of these cities is an important emerging area of study. Access
             to nature is vital to the physical, mental, emotional and social health of
             humans and their communities. Our increasing urbanization is depriving
             current and future generations of exposure to functional, productive green
             space, contributing to rising crime, violence, social alienation, poverty,
             hunger, and other individual and community-level dysfunctions (Kuo, 2001).
             This session will examine the effects of urbanization on Chicago, an older
             While it may seem strange to use the term "ecosystem" when discussing a
             major city, but urban ecosystems exist around the country (PBS, 2003). An
             urban ecosystem is the community of plants, animals, and humans that
             inhabit the urban environment. It is an area physically dominated by man-
             made structures, such as buildings, roads, sewers, and power lines.
             However, it also contains a rich patchwork of green spaces â€" parks, yards,
             street plantings, greenways, urban streams, commercial landscaping, and
             undeveloped lots â€" that make up the urban ecosystem.
             As separate and fragmented as these elements may appear, they collectively
             make up a single organism (PBS, 2003). The urban forest is one example. It
             is easy to imagine all of a city's trees â€" whether in a park, on a street,
             in an undeveloped parcel, or in a backyard â€"joined together in a citywide
             system, just as they appear to be when viewed from an airplane. This urban
             forest may be different than an undisturbed rural forest, but many of its
             There are major differences between urban ecosystems and other ecosystems
             that have been less dominated by humans (PBS, 2003). Urban ecosystems are
             typically highly disturbed sy...