Repeat Historical Photography of Twentieth Century Vegetation Change in Wyoming and Montana

Historical photographs of landscapes ranging from hillslopes and mountain peaks to wetlands are available for nearly any area in the western United States (Rogers et al. 1984). As a first approximation, environmental changes of the past century can be assessed by finding the site of an historical photograph, relocating the original camera position, and making a new photograph of the same scene at the same scale and dimension. Differences between historical and repeat photographs provide a basis for identifying and even quantifying changes, while the new photograph establishes a benchmark for future evaluation (Malde 1973). Ground repeat photography is a simple, inexpensive, and elegant tool for reconstructing past environmental changes and monitoring future changes, and is particularly well-suited for the open landscapes of the western U.S. (Hastings and Turner 1965, Rogers 1982, Gruell 1983, Humprey 1987, Veblenand Lorenz 1991, Webb 1996).

Historical photographs (ca. 1860-1930) are readily available in a variety of archives. For example, one of the requirements in the early days of the U.S. Geological Survey was for its geologists to photograph outcrops they were describing and mapping. Consequently, a rich archive of both high quality negatives and positives of western landscapes, many taken with large format cameras, has accumulated at the USGS Photo Library in Denver, Colorado (for more information, contact Joe McGreggor at

One of the more prolific contributors (2100 large format images) to the USGS Photo Library was the renowned geologist Nelson Horatio Darton (1865-1948; Figure 1). G.K. Gilbert, one of the grand figures of American Geology (Baker and Pyne 1978) invited Darton to join the Geological Survey in 1886 (King 1949; Monroe 1949; Malde, unpublished). Darton was influenced by Gilbert, who appreciated the scientific value of good, annotated photography and actually was one of the first to describe methods and applications for repeat photography (Gilbert 1904).

Nelson Horatio Darton
Figure 1. Nelson Horatio Darton (1865-1948)

As a mere 20-year old, Darton immediately took an interest in geological photography, initially with a half-plate (5 x 8-inch) camera and in 1891, with an 8 x 10-inch camera. Darton worked in a number of places, including the American Southwest, the central Rockies, the central Plains, and even the island of Cuba. Between 1896 and 1906, he took 800 photographs in the Great Plains/central Rockies. Darton worked on the geology of the Bighorn Mountains, and crisscrossed by horse and wagon many of the areas in Wyoming covered with Utah juniper (Juniperus osteosperma). In August 1998, Steve Tharnstrom and Julio Betancourt (USGS) began matching historical photographs throughout Wyoming, taken by Darton and his contemporaries at USGS in the early part of this century. This repeat photography effort is intended to document changes in the distribution of Utah juniper (Juniperus osteosperma) and other key plant species during the past 100 years (Figures 2-7).

Baker, V.R. and S. Pyne. 1978. G.K. Gilbert and modern Geomorphology. American Journal of Science. 278: 97-123.

Darton, N.H. 1906. Geology of the Bighorn Mountains. United States Geological Survey Professional Paper 51. 129 pages + 46 plates.

Gilbert, G.K. 1904. Variations of Sierra glaciers. Sierra Club Bulletin 35: 113-116.

Gruell, G.E., 1983, Fire and vegetative trends in the northern Rockies; Interpretations from 1871-1982 photographs: USDA, Forest Service General Technical Report INT-158, 117 p.

Hastings, J.R. and R.M. Turner. 1965. The changing mile: An ecological study of vegetation change with time in the lower mile of an arid and semiarid region. University of Arizona Press, Tucson, 317 p.

Humphrey 1987. 90 years and 535 miles: Vegetation changes along the Mexican border. University of New Mexico, Albuquerque.

King, P.B. 1949. Memorial to Nelson Horatio Darton. Geological Society of America Proceedings., Annual Report for 1948, p. 145-170.

Malde, H. 1973. Geologic benchmarks by terrestrial photography. U.S. Geological Survey Journal of Research 1: 193-206.

Malde, H. 1983. N.H. Darton as a geological photographer. Unpublished manuscript.

Monroe, W.H. 1949. Memorial, Nelson Horatio Darton (1865-1948): American Association of Petroleum Geologists Bulletin 33: 116-124.

Phillips, W.S. 1963. Photographic documentation, vegetational changes in northern Great Plains: University of Arizona, Agricultural Experiment Station Report 214, 185 p.

Rogers, G.F. 1982. Then and now: A photographic history of vegetation change in the central Great Basin Desert: Salt Lake City, University of Utah Press, 152 p.

Rogers, G.F., H. E. Malde, and R. M. Turner. 1984. Bibliography of repeat photography for evaluating landscape change: Salt Lake City, University of Utah Press, 179 p.

Veblen, T.T. and D. C. Lorenz. 1991. The Colorado Front Range: A century of ecological change: Salt Lake City, University of Utah Press, 186 p.

Webb, R. H. 1996. Grand Canyon, a century of change: Rephotography of the 1889-1890 Stanton Expedition: Tucson, University of Arizona Press, 320 p.

Figure 2a
Figure 2a. 1904 Darton photo (#1003) of the "Tensleep and Amsden formations on west side of Tensleep Canyon, Bighorn Mountains. Looking northeast. Shows Tensleep Sandstone and basal cross-bedded sandstone of Amsden on Little Horn Limestone." The foreground vegetation, where Darton's horses are grazing, is mostly sagebrush. The riparian gallery along Tensleep Creek includes cottonwoods and willows. The larger trees dotting the hillside are ponderosa pine, whereas the smaller shrubs include Utah juniper and little-leaf mountain mahogany. Darton took this photograph from a wagon road in Tensleep Canyon.
Figure 2b
Figure 2b. 22 August 1998 photo and data taken by Steve Tharnstrom and Julio Betancourt (Station 99 matches Darton #1003; N44°3.828' W107°22.152'; Washakie Co., Wyoming, 1429 m elevation). Note that the sagebrush has been replaced by grasses in the foreground and both Utah and Rocky Mountain junipers. The greatest change is on the hillslope and cliffsides, which are being invaded by Utah juniper. The wagon road has now been replaced by U.S. Highway 16.
Figure 3a
Figure 3a. June 1922 Lee photo (#2273). "North Wall of Tensleep Canyon, showing Amsden Formation overlain by Tensleep Sandstone." W.T. Lee was a contemporary of Darton's and also an avid geological photographer. This photograph was taken ca. 100 m west of Figure 2a and b and includes a protion of the cliff in Darton's photograph.
Figure 3b
Figure 3b. 23 August 1998 photo and data taken by Steve Tharnstrom and Julio Betancourt (Station 106 matches Lee #2273; 44°03.946' W107°22.531', Washakie Co., Wyoming). Note the dramatic increase in Utah juniper since 1922. U.S. Highway 16 in foreground.
Figure 4a
Figure 4a. 1904 Darton photo (#1006). "Fault on Canyon Creek 3 miles northwest of Rome, west slope of Bigrnorn Mountains. Looking northeast. Little Horn Limestone with cavers to left overlain by Amsden and Tensleep beds, the last on high summit. To right of middle, Tensleep sandstone nearly vertical in contact with horizontal Madison Limestone at fault."
Figure 4b
Figure 4b. 23 August 1998 photo and data taken by Steve Tharnstrom and Julio Betancourt (Station 103 matches Darton #1006; N44°01.639' W107°29.595', Washakie Co., Wyoming). Note the increase in Utah juniper densities in both the foreground and along the mountain front.
Figure 5a
Figure 5a. Mansfield 25 August 1936 photo (#1059). "Paleozoic beds, morainic materials in foreground." North wall of Tensleep canyon, from Forest Service Road 18, opposite U.S. Highway 16.
Figure 5b
Figure 5b. 24 August 1998 photo and data taken by Steve Tharnstrom and Julio Betancourt (Station 107 matches Mansfield #1059; 44°07.207' W107°14.956', Washakie Co., Wyoming, ca. 2200 m). The north wall of Tensleep Canyon and moraines in the foreground have experienced a dramatic increase in tree cover since 1936. This increase includes limber pine, Utah juniper and Rocky Mountain juniper. This photo pair illustrates one of the difficulties in interpreting repeat photography. In 1910, a large fire started by a poacher swept the upper part of Tensleep Canyon. This was one of many fires across the western U.S. in 1910, the year that inspired the Smokey the Bear policy and aggressive fire suppression. Rather than tree encroachment or invasion, this photo pair reflects the woodland recovery after fire.
Figure 6a
Figure 6a. 1905 Darton photo (#1098). "Looking east through canyon of No Wood Creek, 3 mi. below No Wood Wyoming, Tensleep Sandstone on the left."
Figure 6b
Figure 6b. 25 August 1998 photo and data taken by Steve Tharnstrom and Julio Betancourt (Station 120 matches Darton #1098; 43°38.753' W107°22.798'). Note increase in curl leaf mountain mahogany on canyon walls.
Figure 7a
Figure 7a. 19?? Heald, K.C. photo (#177) "Tensleep sandstone faulted against older beds at gorge in No Wood Valley 4.5 miles north of No Wood Post office, Wyo." The dominant shrub on the steep hillslopes in curl leaf mountain mahogany.
Figure 7b
Figure 7b. 25 August 1998 photo and data taken by Steve Tharnstrom and Julio Betancourt (Station 121 matches Heald #177; 43°38.08' W107°22.884'). Note increase in the density of curl leaf mountain mahogany and Utah juniper.