Proximity between urban realm and wilderness has been a salient feature of Northern American territorial patterns since European settlement. Even today such proximity, although drastically reduced, in some cases endures. Nonetheless, the topological relation betwen areas of extensive development and wild land is changing: if the history of urban America has been a history of cities in the wilderness, today vast urbanized regions frequently encompass wild enclaves, areas we look upon as wildernesses in the city. These wilderness remnants may be protected areas engulfed by urban growth, or areas that have not been developed due to their orographic or hydrographic features, or areas that have been developed and subsequently abandoned. Varying in form and physiographic features, they range from large natural systems to minute green interstices widespread in the urban fabric