Pinus bungeana – lacebark pine Pinus cembra – Swiss pine Pinus gerardiana – Chilgoza pine Pinus koraiensis – Korean pine Pinus pinea – Mediterranean stone pine Pinus pumila – Siberian dwarf pine Pinus sibirica – Siberian pine New World Pinus albicaulis – Whitebark pine Pinus cembroides – Mexican pinyon Pinus coulteri – Coulter pine Pinus culminicola – Potosi pinyon Pinus edulis – Two-needle piñon or Colorado pinyon (when grown in Colorado) Pinus johannis – Johann's pinyon (includes P. discolor – Border pinyon) Pinus monophylla – Single-leaf pinyon Pinus orizabensis – Orizaba pinyon Pinus quadrifolia – Four-leaved pinyon or Parry pinyon Pinus remota – Papershell pinyon or Texas pinyon Pinus sabiniana – California foothill pine Pollination and seed development The pine nut (seed) species will take a time that depends on the exact species (e.g., 36 months for a stone pine seed) to complete its maturity; to reach full maturity, the environmental conditions must be favorable for the tree and its cone. For some American species, development begins in early spring with pollination. A tiny cone, about the size of a small marble, will form from mid-spring to the end of summer; the premature cone will then become and remain dormant (with a cessation of growth) until the following spring. The cone will then commence growth until it reaches maturity near the end of summer. The mature piñon pine cone is ready to harvest ten days before the green cone begins to open. A cone is harvested by placing it in a burlap bag and exposing it to a heat source such as the sun to begin drying. It takes about 20 days until the cone fully opens. Once it is fully open and dry, the seed can be easily extracted in various ways. The most common and practical extraction method used is the repeated striking of the burlap bag containing the cone(s) against a rough surface to cause the cone(s) to shatter, leaving just the job of separating by hand the seed from the residue within the bag. Another option for harvesting is to wait until the cone opens on the tree (as it naturally will) and harvest the cone from the piñon pine, followed by the extracting process mentioned above. Fallen seeds can also be gathered beneath the trees. Ecology and status Because pine nuts are an important food source for many animals, overharvesting of pine nuts threatens local