The state tree of New Mexico is the Pinyon Pine (Pinus edulis). The Pinyon pine is also known as Colorado pinyon, Rocky Mountain pinyon, nut pine, and two-needle pinyon. This pine tree is found throughout the southwestern United States particularly in Utah, Arizona, Colorado, and New Mexico, as well as southern Wyoming, eastern Nevada and California, and western Oklahoma. Look for pinyon on dry mountain slopes, mesas, and plateaus. Pinyon often grows with juniper and together they make up one of the more common forest types in the western United States.
This tough pine grows in almost any soil type, including rocky terrain. If the topsoil covering is shallow, the trees will not grow as fast and when the topsoil covering is deeper. The branches hold to the tree near the ground, so any tree litter tends to become a nutrient source for that tree.
The pinyon seed germinates when there is adequate water and shade. These conditions are more often found in early spring or if there is a wet summer. The seedlings are usually near the base of an existing tree that can provide filtered light. Once established, pinyon is both cold and drought tolerant.
Pinyon is a slow-growing, long-lived pine. It can be found growing like a low bush with very crooked branches and distorted truck. It can be found 50 feet tall with a trunk diameter of 40 inches. Pinyon can live for 500 to 1,000 years. A tree in Utah was tested to be 973 years of age. Pinyon is a tree for the wild and is not often found in landscaped areas. Trees with a regular source of water maintain their rounded to conical shape and would be a good selection for climates that provide a cold winter. Pinyon can also be planted in row hedges as an effective windbreak.
The pine needles are 4 inches long and grow in pairs. The needles are thick, with a slight curve and are yellow-green or blue-green. They can persist on the tree for as long as 9 years. The overall shape of a young pinyon is conical. As the tree ages, the crown tends to spread and look irregularly shaped with a generally flat top.
Pine cones are 2 inches long and can grow in clusters of four. Cones need 2-3 years to mature and produce seed. Pinyon is both monoecious (separate male and female trees) and dioecious (trees have both male and female cones). Pollen is carried by the wind and the cone/fruit produces seed. Some studies indicate the seedlings from monoecious seed is more vigorous.
A pinyon starts to produce cones when it reaches 25 years of age and will stay productive through 200 years of age. When the cone matures, the cone sheds the seeds and drops to the ground. Seed production varies on a 3 to 7 year cycle. Seed production is also dependent on adequate water being available. Seeds are dispersed by birds and small animals. Some birds store the seeds which also helps with producing the seedlings. The birds who store the seeds include Clark’s nutcracker, stellar jay, pinyon jay, Mexican jay, and scrub jay. Without these birds storing up seeds for the winter, there would be many fewer pinyon seedlings.
Pinyon roots systems are shallow and widely lateral spreading, as well as having a single tap root that reaches 20 feet into the soil in search of water. The lateral roots are mostly at a depth of 6 to 16 inches. The lateral root spread will most likely exceed the crown spread. The growth habit of the root system means that the pinyon will crowd out its neighbors by limiting the availability of nutrients and water.
Pinyon is a good food source for a variety of animals in the wild. Pinyon is browsed by deer, elk, sheep, horses, and small mammals. The seeds are eaten by small mammals, such as chipmunks and squirrels, and birds.
There is a history of the early people using the pinyon seeds as part of their diet. The pitch was used to waterproof vessels. The trees have commercial value for their wood. The wood is used for fuel, structural timbers in mines, fence posts, cross pieces for railroad ties, and pulp. The trees are a standard Christmas tree in the Southwest, and the branches make fragrant wreaths and swags. The needles have some medicinal value as a diuretic and an expectorant. The needles are also used to make a tea. The seeds can be roasted and salted as a snack food.
Sources
Pinyon Pine, US Forest Service, http://www.fs.fed.us/database/feis/plants/tree/pinedu/all.html
Pinyon Pine, The Gymnosperm Database, http://www.conifers.org/pi/pin/edulis.htm
Pinyon Pine, Virginia Tech, http://www.cnr.vt.edu/Dendro/dendrology/syllabus/factsheet.cfm?ID=178
Pinyon Pine, New Mexico State University, http://medplant.nmsu.edu/pinon.htm
