Santa Catalina Highway, near Tucson, Southern Arizona - 2006

Two ranging poles were placed near the positions of two sets of saguaros in order to determine their heights, and hence approximate ages. Most were established in the 1890s, after livestock grazing and the removal of fine fuels had begun in the area. Several small saguaros have become established since the fire; one is to the left of the left-hand ranging pole, another is hidden behind the blue paloverde at the center. Buffelgrass, an invasive nonnative grass, is abundant at this site and surrounds the desert hackberry) in the foreground. (Raymond M. Turner).