Piñon trees or pinyon trees are a family of pine trees native to southwestern North America. The piñon can be found in habitats as far south as Mexico and as far north as Fort Collins, Colorado. Piñon pines are a semi-desert tree that require little water and that produce piñon nuts or pine nuts, as well as fragrant and long-burning firewood. The piñon is also New Mexico's official state tree.
There are eight different subspecies of piñon tree, plus four related piñon-type trees that are also typically known as piñons. Of these, the four most common are the Mexican piñon, the Singleleaf piñon, the Colorado or "two-leaf" piñon, and the Parry piñon. All twelve types of piñon tree produce edible nuts and grow in similar environments.
Piñon trees are typically found in elevations between 4000 and 9000 feet. They can survive in areas that receive only twelve inches of rainfall a year. Once a piñon tree is established in the ground, it does not need additional watering. The piñon prefers dry, rocky soil, but will adapt to a wide range of soil conditions.
Piñon trees grow slowly, only reaching their full height of 20 to 25 feet after many years. The trees are noticeably bushy, with short trunks, branches that grow horizontally at right angles to the trunk, and rounded crowns. The needles of the piñon are one to two inches long. Most piñon needles have smooth edges; however, the needles on the Mexican Piñon have small, fine teeth. Different species of piñon may be identified by the way in which their needles grow. The needles on the Singleleaf piñon grow singly. On the Colorado and Mexican piñon, the needles grow in pairs, while on the Parry piñon, needles grow in clusters of four.
In addition to its needles, a piñon tree may also produce cones and piñon nuts. Piñon nuts were a staple food among Native Americans in the Southwest and are still prized today for their unique flavor. A piñon's cones are usually about two inches long and have an irregular, vaguely round shape. The nuts are reddish or yellowish in color and may be one to three inches long. Piñon trees will only produce nuts if several trees are in the area to pollinate one another. An un-pollinated piñon tree may produce cones, but the cones contain no piñon nuts.
In addition to producing piñon nuts, piñon trees are grown as windbreaks and as ornamental elements in landscaping. The trees also feed a variety of southwestern wildlife, especially birds. The piñon jay relies heavily on piñon nuts for its food, as do birds like the Mexican jay and the Clark's nutcracker. Squirrels, bears, and deer also eat piñon nuts.
In 1994, forestry workers in Colorado began noticing the first stages of a disease now known as "piñon decline." The disease is peculiar to the piñon. It begins with a clear sap leaking from the larger branches. Then, the needles begin to turn brown and drop from the tree. Dead branches should be removed from piñon trees suffering from piñon decline. Although excess watering does not cause piñon decline, it can make the disease progress more rapidly, so trees with piñon decline should be limited to ten inches of water per year.