We must look at a tree in total when looking for a problem. Trees five as a part of a system. When something happens to the system, it affects the trees within the system. Sustainable means to use resources to manage the system. Unfortunately when trees are taken out of their natural environment and placed in the human environment as street trees, maintaining a sustainable landscape becomes very difficult.
Trees do live in urban environments but it is very difficult.
The trees that are selected for urban areas are trees such as honeylocust which are not native but will tolerate and grow in most urban areas. The trees that do live in the city do not live in a sustainable landscape. In order to develop a sustainable landscape, there must first be an ecological match of the tree to the environment and the site to the tree. The site can be modified to make it compatible with the tree's specific needs. People will often ignore factors such as the seed source, the ecological factors of the tree, the tree's origin and natural habitat, and the adaptability of the root stock.