Along the Colorado Plateau’s high-standing Mogollon Rim in northern Arizona’s Coconino National Forest stands a small patch of big trees that matured well before Europeans came to North America. Massive ponderosa pines, and even pinyon pines and western junipers, tower above the forest floor, shutting out all but the most shade-tolerant competitors. Few places like this one still exist anywhere in the United States, even on national forest lands. A tourist hoping to see all the diversity that earliest European arrivals found commonplace in the western landscape must seek out a wide scattering of isolated enclaves across the region. Western forests no longer contain the grand glades and lush thickets that our forerunners encountered because most woodlands, especially those owned by the public, largely serve a wide variety of human purposes, as campsites or home sites, board-feet of lumber, potential jobs, recreational playgrounds, and even temples of the spirit. We also rely on forests to maintain habitat for endangered species and seed banks for restoring depleted biodiversity—and to provide us with clean air and water, stable hillside soils, and flood control in wet years. Forests must perform these roles while being consumed, fragmented by roads, and heavily eroded. But there is no guarantee that these most beloved and iconic of natural resources can sustain such a burden. Federal, state, and local government agencies oversee and regulate western U.S. forest lands and their uses, trying to manage the complex and only partly understood biological interactions of forest ecology to serve public needs. But after nine decades of variable goals, and five decades of encroaching development, western woodlands are far from healthy. Urban pollution and exotic tree diseases, some brought by humans, are killing pines, firs, and oaks. Loggers have more than decimated the oldest mountainside forests—most valuable for habitat and lumber alike—with clearcutting practices that induce severe soil erosion. Illegal clearings for marijuana farms are increasing.
Contributions to groundwater from National Forest lands in the Mississippi Embayment: a century-long simulation