There is not a perfect correspondence between Rose's strategies and Bromley's categories. Most urban land in the United States is defined as either private or public property. Yet such land may be more like common property than is usually recognized. Instead, for example, the private owners of land next to a river may not be permitted to install underground oil storage tanks. Those aspects of land use that affect the community's quality of life or shared environment are managed almost like common property.
Environmental instability gives commoners an incentive to share risks.
Social stability allows or forces them to preserve resources for future generations. For example, in many Alpine villages, herds are private property but summer pastures are common property. To avoid overgrazing and free-riding, individual farmers cannot graze more sheep and goats on the summer pastures than they can feed privately over the winter. Access to the summer pastures helps to guarantee all families, whatever their private resources, a chance to earn a living. Environmental instability and social stability are usually associated with rural places.