Singleleaf Pinyon

• Singleleaf pinyon (Pinus monophylla) trees grow between 15 and 30 feet tall. Young trees have a pyramidal form, while mature trees are more irregular in appearance. They have single bluish- or greenish-gray needles and yield half-inch-long seeds within rounded cones. Most trees do not begin producing large crops of seeds until they are at least 100 years old. Singleleaf pinyon trees are rarely cultivated in home landscape settings, according to M. Kat Anderson from the U.S. Department of Agriculture's Natural Resources Conservation Service.
  
  

Two-Needle Pinyon

• Two-needle pinyons (Pinus edulis) are small trees or large shrubs. They average between 10 and 30 feet in height. Trees that grow at higher elevations usually have single trunks and greater height, while trees at lower elevations tend to be more shrublike, with multiple trunks. They have brownish-red bark, spreading or sprawling crowns and clusters of evergreen needles that appear in groups of two. This species is more often cultivated than singleleaf pinyon. Two-needle pinyons at least 25 years old produce oval-shaped or rounded cones and light-brown seeds.
  
  

Pinyon Seeds

• Pinyon nuts were once a primary source of nutrition for American Indians in the southwestern U.S. Many tribes still collect the cones and harvest the flavorful seeds. They use the nuts as ingredients in cakes and soups; they also roast, shell and eat them, or sell them on the gourmet food market. Wild animals compete with humans for the seeds. Deer, bears, squirrels, rabbits, turkeys and a variety of birds such as scrub jays, Clark's nutcracker, pinyon jays and Steller's jays feed on the nuts. These birds also help the trees reproduce by scattering the seeds.
  
  

Liabilities

• Several diseases and insect pests attack pinyon trees. The armillaria fungus rots the wood from the inside, while black stain root disease damages the sapwood. Pinyon decline is characterized by dead branches and discolored yellow or red needles. Common insect pests include the larvae of Ips or engraver beetles, which attack the wood below the bark; pinyon spindlegall midge larvae form galls on pinyon trees; and pinyon tip moth larvae feed on the twigs, causing dieback.