Since the late 19th century the engineering professions have done a masterful job of ameliorating filth and spread of disease in our cities, including the provision of safe water supply, sanitary disposal of human waste and refuge, and public health regulations (Grove et al., 2016). This concept of the Sanitary City gave way in the 1990’s to the concept of the Sustainable City. Today we recognize the role that metropolitan regions play in the conservation of biological diversity, and the ecosystem services that support human health and well-being.
These ecosystem services include the production of food, fresh water, medical resources, climate and local weather regulation, moderation of extreme events and waste-water treatment. In addition to life-support functions, they confer many intangible aesthetic, cultural and spiritual benefits as well.
The Sanitary City was able to provide us with a cleaner and safer built environment, at a time when our forests seemed remote and wild. The benefits these forests provided urban society was a foregone conclusion or simply not recognized. But our world has changed. Today municipalities are just a small portion of larger metropolitan regions. Our growing metropolitan regions annex forest land and influence the use and condition of adjacent rural forests.
This urbanized forest, inside and outside municipal boundaries, has become a new and relatively unknown component of the forest’s biological diversity. A growing urban population and the decentralization of government in our country mean that city and county authorities are responsible for an increasing portion of the forest’s biological diversity. Foresters and engineers now have the opportunity and responsibility to expand their traditional roles by incorporating a more ecological perspective into their work, and supporting the metropolitan sustainability. How we organize ourselves to sustain biological diversity in urbanizing forests will directly influence the health and well-being of future generations.