The basic quality of an urban forest is its dependency on the city to which it is connected. The urban forest can take the shape of many forms. It could be in the form large tracts of land with dense tree growth on the perimeter of the city, or it can be distributed throughout the city with trees planted in streets, vacant lots, and greenways. The urban forest may be defined as "the sum of all woody and associated vegetation in and around dense human settlements." (Miller, 27) This includes tree lined streets, parking lots, school yards, parks, river banks, cemeteries, freeway interchanges, abandoned rail lines, roof gardens and of course front and backyards where there are trees. In essence the urban forest could be any vegetation or trees in and around a city.