University of California

Photo Comparisons

In the 1930s, U.S. Forest Service researchers, including F.G. Renner, A.L. Hormay and M.W. Talbot, compiled an extensive archive of rangeland photographs, primarily around California’s San Joaquin Valley.  Thousands of photos were consecutively numbered, duplicated, documented and archived in envelopes.  Most of the photos were close-ups of vegetation lacking a geographic context and thus impossible to find and re-photograph.  In 2010, 75 sites were selected that contained enough background landscape in the photos to potentially re-locate, re-photograph, and GPS. Active and retired extension colleagues, ranchers, and NRCS range professionals collaborated to relocate and re-photographed 20 sites. These photo comparisons document vegetation and land used change on California rangelands.

Finding Photo Sites

Finding photo sites was a challenge. In several cases, locked gates limited access to areas where photos were previously taken. Additionally, many sites had experienced significant change and were difficult to recognized. To relocated sites, two or more observers had to agree on the site and how to best position the camera.

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