Changing Mile Revisited

The Changing Mile Revisited documents vegetation changes in Southern Arizona and Northern Mexico as recorded by comparing benchmark photographs from the late 1800s and early 1900s with photographs taken at the exact same locations in the early 1960s and the late 1990s. This landmark study records the persistent decline of the saguaro in many locations, as well as the general increase of mesquite, palo verde, and woody shrubs. The authors discuss multiple reasons for these changes that include climate change (increased temperature and atmospheric carbon dioxide concentrations); extensive cattle grazing; arroyo cutting; fire suppression and urbanization. This striking portrait of “the prevalence of change in a seemingly changeless place” is indispensable for both historians and ecologists.