Field trips

Ecological Changes around the San Francisco Peaks Revealed by Modern Repeats of Historical Photographs

John L. Vankat, Monday, Sept. 8, 8 a.m. to 4 p.m.

Join ecologist John L. Vankat on a full-day field trip exploring ecological change in the San Francisco Peaks region through repeat photography. Participants will visit nine historical photopoints, comparing 19th-century landscape images with present-day views to understand shifts in forest density, fire history, and grassland loss. This immersive experience will offer valuable insight for land managers, researchers, and students interested in long-term ecosystem change. The all-day tour involves light hiking (~2 miles) and visual analysis of century-long transformations in this iconic high-elevation landscape. Please bring water. Your registration fee includes a boxed lunch.

The following is a list of sites to be visited. I have repeated a historical photograph dating to 1871-1900 at each site. We will compare the historical photographs with my repeat photographs and today’s landscapes to see and understand how the past has transitioned to the present.

1) Interior of the Walker Lake volcanic cone. An 1871 panorama shows the low-density of pre-20th century ponderosa pine forest. Today, the site has dense, unburned forest stands mixed with open grassland stands where the 1996 Hochderffer Fire burned at high severity.

2) Southeast-facing, exterior slope of the Walker Lake volcanic cone. The 1887 view toward the San Francisco Peaks shows forests, grasslands and sites of past crown fires. This contrasts with today’s homogenously dense forests.

3) Southeastern base of the Hochderffer Hills toward Fern Mountain and Hart Prairie. The 1880s photograph shows an extensive landscape with grassland in the foreground and background and low-density forest in the midground. The landscape is mostly forested today.

4) Southeastern base of the Hochderffer Hills toward the San Francisco Peaks and Hart Prairie. The 1890 photograph shows grassland in the foreground, relatively open forest in the midground, and Hart Prairie and the San Francisco Peaks in the background. Tree densities have increased at nearly all elevations, except in an area where trees were cut and removed to restore a section of Hart Prairie.

5) Hart Prairie and the San Francisco Peaks to the east-southeast. The 1890s photograph shows a stand of trees in the middle of Hart Prairie, as well as a fence, which indicates livestock grazed in Hart Prairie at that time. Changes are similar to those at the previous site, but there is a closer view of the area where grassland was restored.

6) Hart Prairie and the San Francisco Peaks to the east. This 1890s photograph shows more of Humphreys Peak than the previous historical photograph, including a large, high-elevation area burned by crown fire. My repeat photograph illustrates increased tree cover.

7) Northern Hart Prairie and the San Francisco Peaks. This 1885 photograph by accomplished photographer John Karl Hillers was taken near the north end of Hart Prairie and is a well-known image of the San Francisco Peaks. It includes wagon tracks in the midground, wagons and tents beyond the tracks, and initials carved in the trunk of a nearby aspen. Despite the popularity of this photograph, its photopoint was unknown until I did extensive searching. The view from the photopoint was then restored by the Forest Service. My repeat photographs show the site before and after that restoration.

8) Northern Hart Prairie and the San Francisco Peaks. This 1890s photograph of Hart Prairie and the Peaks shows fencing erected for livestock and provides an excellent view of the extensive grassland that formerly comprised Hart Prairie. The historical photograph also shows a large area on the Peaks that had burned at high severity.

9) Side meadow connected to northern Hart Prairie. This 1900 photograph shows an open site where the route for the Grand Canyon-Flagstaff Stagecoach Line entered Hart Prairie from the west. Today, the former grassland has been replaced by dense mixed conifer forest.