Station M (Hart Prairie Preserve, Coconino County, Arizona): Porcupine Tree

Several different animals use ponderosa pines for food and shelter. Look closely at this tree, a porcupine has gnawed away at the bark to get to the nutritious cambium or inner bark. These animals are slow-moving, have few natural enemies, and are well camouflaged among the pine needles because of their needle-like armor of quills. The mountain lion is one of the few animals that prey on them, flipping them over and exposing their unprotected belly. Because of their habit of dining on bark, foresters used to consider porcupines a nuisance animal, and Forest Service rangers were issued .22 caliber pistols to shoot them on sight. Now they are protected by law, and it is recognized that they are integral to the ecosystem. Unless they girdle the tree (eat a band all the way around the trunk), the tree will survive. Porcupines don't subsist entirely on bark; they also eat tender leaves and grasses in the spring and summer, and pine needles and mistletoe in the winter.