Before about 1880, Ponderosa pine forests throughout the American west were open, park-like habitats. Between 1880 and 1920 the forests began to change. Saplings started crowding the open spaces that had previously separated mature pines. People expected most of them to die off, leaving only the most hearty young trees to live. But that's not what happened. All the saplings grew, until the forest became a grove of tall spindly trees so tightly-packed that even foot passage between them was no longer possible. Such groups of trees are called "dog-hair" for obvious reasons. Even in the early years of the 20th century, naturalists were deducing that the dog-hair forest pattern was a consequence of suppressing the wildfires that had, in years past, regularly burned out the smallest and weakest seedlings so that only a few survived in any given area. People like John Muir pointed to the role of grazing in the process, too, noting that cows and sheep removed the tough grasses that kept seedlings from sprouting to begin with, and also compacted the soil so that grasses couldn't easily grow back later on (Footnote 8).
Pine Ridge was already settled by ranchers when the Cheyenne fled across Sowbelly that January of 1879. Forty-five years later, in 1924, the geologist Jesse Earl Hyde came west from Case Western Reserve University and photographed the canyon and its rock outcroppings. We were fortunate enough to find these pictures in an online archive maintained by the Department of Geological Sciences at CWRU and were graciously given permission to use them (Footnote 9). They document the development of the dog-hair forest pattern in Sowbelly over the 80 years between Hyde's visit and our move to Sowbelly in 2004, and show that it was correlated with grazing.
Early-stage dog-hair thickets are clearly visible in several of Hyde's images, as are fence lines that prove grazing was taking place at the same time. There is no other reason people would invest the money for wire and the back-breaking labor for making posts, digging postholes, and stringing wire over miles of rough country. Over the next 80 years the cattle industry grew and so grazing continued. The damage got a lot worse. The degree of pine overgrowth visible in the photos we took of the same places in 2004 is nothing short of astounding.
What's even more astonishing, however, is comparing after-the-fire photographs of the same areas to the ones from both 1924 and 2004. In every case, the places where the fire burned most severely were also the places where there had originally been very few trees. Furthermore, in places where the forest trees had been well-spaced but moderately dense, the fire killed a proportion and spacing of trees that essentially restored the earlier configuration. Of course, now there were burned trees between the healthy ones instead of the "clean" open grassy space of the 1920s, but the pattern of restoration to the original configuration was unmistakable (Figures 28-33).