PS 333.2 - September 1904
David Griffiths
The Santa Rita Experimental Range (SRER) database includes an archive of photographs taken repeatedly over the years from 128 sites throughout the range. Currently, 119 Photo Stations out of 128 are actively monitored. The earliest photographs were taken by David Griffiths between 1902 and 1905 at 16 different locations (PS 219, 220, 221, 222, 224, 228, 229, 230, 231, 233, 234, 251, 332, 333, 334, and 335). The average interval between photographs is approximately 15-20 years, but some locations have repeat photographs made twice a year for a period of up to eight years (1950-1960). Since 2000, photographs have been taken on average every other 6 years, in March (114 locations) or October (5 locations). Since 2024, photographs have also been taken every August at a subset of 18 Photo Stations out of the 114 March locations.
The database includes, for each picture, a text written by the photographers that describes the vegetation and other attributes of the scene and the UTM coordinates for each Photo Station location. A comprehensive list of plant species recorded at the August Photo Stations can be found on the Flora page. In these locations, all annual and perennial plant species growing within a 40 m² area in front of the camera have been recorded to document species richness and vegetation changes after each monsoon season. The annual recordings are also part of the initiative to update the Flora of the SRER.
PS 333.2 - October 2018
Mitchel McClaran
Photographs and texts for a Photo Station location can be accessed by selecting the Photo Station number from a list or from a hyperlinked map of Photo Station locations on the SRER (Find Photos on a Map). Mitchel McClaran recorded the UTM coordinates of Photo Stations with a Global Positioning receiver between 1998 and 2000. The coordinates are projected in the NAD83 datum using the GRS1980 spheroid. The images can be downloaded as Tagged Image Format files (*.tif), as Joint Photographic Experts Group (*.jpg), or copied as images in the Graphical Interchange File format (*.gif).
The images are accompanied by a Photo Archive number that identifies the location, direction, year, and month of the photo. For example, the Photo Archive number 45.1.1948.06 identifies the image as being made at photo station 45 (or PS 45), looking in the direction that is closest to north and on the east side of north, in the year 1948, and the sixth month or June. The direction code ranges from 1 to 7: about half of the locations have photographs taken in only one direction, and about 40 percent have two directions. One location (PS 42) has seven directions that are arranged to provide a nearly 360-degree view. When more than one direction is included for a photo station, the value of 1 was assigned to the direction closest to north on the east side of north, and subsequent values increased in a clockwise direction.
The Retake History of the Photo Stations is summarized in the file below under “Photo Station Retake History Data and Figures". The file includes figures summarizing the Number of Photos taken per Year, the Number of Directions by Photo Station, and the Number of Retakes by Photo Station Direction. The figures are provided for preview below.
References
McClaran, Mitchel P.; Angell, Deborah L.; Wissler, Craig. 2002. Santa Rita Experimental Range digital database: user’s guide. Gen. Tech. Rep. RMRS-GTR-100. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 13 p.
