The Evils of Pinyon and Juniper
Charles E. Kay. 2010. The Evils of Pinyon and Juniper. Mule Deer Foundation Magazine Vol 10(5): 6-13
Dr. Charles E. Kay, Ph.D. Wildlife Ecology, Utah State University, is the author/editor of Wilderness and Political Ecology: Aboriginal Influences and the Original State of Nature [here], author of Are Lightning Fires Unnatural? A Comparison of Aboriginal and Lightning Ignition Rates in the United States [here], co-author of Native American influences on the development of forest ecosystems [here], and numerous other scientific papers.
Full text with photos (click on photos for larger images):
PINYON PINES and upright junipers are found throughout the West. Ash and red berry juniper occur in Texas, while western juniper is most abundant in the interior Pacific Northwest. One-seeded and Utah juniper are widespread in Nevada, Utah, and on the Colorado Plateau, whereas Rocky Mountain juniper can be found in Idaho, Montana, and Wyoming. All junipers have small, scale-like leaves and are often called cedars due to their aromatic wood. In fact, the most widely occurring juniper in the East is known as eastern red cedar. In addition to the tall, or upright junipers, there are a few, low-growing species of which horizontal and common are the mostly likely to be encountered.
Pinyons, on the other hand, are represented by only two species. Single-leaf pinyon has only one needle per fascicle, while two-needle pinyon has two needles per fascicle or bundle. Pinyons are abundant in Nevada, Utah, Colorado, Arizona, and New Mexico. Pinyons and junipers are the most drought tolerant of all western conifers. In addition, pinyons and junipers are chemically defended by terpenes and other compounds that inhibit ruminant microbial digestion. Livestock will generally not consume pinyon or juniper and mule deer will generally browse juniper only if the animals are starving. Pinyons and most junipers are also extremely invasive.
Prior to European settlement, it has been estimated that pinyon and juniper covered 7.5 million acres in the West, while today P-J has infested over 75,000,000 acres, a ten-fold increase. Moreover, the number of trees per acre has increased 10 to 100 fold. I have compiled 1,879 repeat photosets in southern Utah and of that total, 1,007 photo pairs depict pinyon and/or juniper. In 96% of those cases, P-J increased, often dramatically. As pinyon and juniper have expanded their range and thickened, the production of shrubs, forbs, and grasses has declined precipitously. In many stands, understory forage production is near zero, and as understory species decrease, soil erosion increases, even on ungrazed sites. In New Mexico’s Bandelier National Monument, for instance, as pinyon and juniper have thickened, understory species have been eliminated, which has lead to a drastic increase in soil erosion threatening the park’s archaeological sites.
Closed-canopy stands of pinyon-juniper are rare in early historical photographs. Instead, most stands once consisted of a few widely-spaced pinyon and/or juniper with abundant grasses, shrubs, and forbs in what could be characterized as a savanna. With time, however, those stands have infilled until today many pinyon-juniper sites have a closed canopy. Pinyon and juniper have also extended their range by invading grasslands, sagebrush, and other plant communities. Historically, old-growth pinyon-juniper was restricted to rocky outcroppings, areas with poor soils, and other fire refugia. Crown-fire behavior in pinyon-juniper is increasingly common in the West today, but there is no evidence that was the norm prior to European settlement and the expansion and infilling of pinyon-juniper woodlands. Only 3 or 1,007 historical photos taken in southern Utah show any evidence of stand-replacing fire in pinyon-juniper until modern times. The same is true in other areas.
