Common Name: Rocky Mountain Piñon

General Information

Pinus edulis is an evergreen shrub or a tree with a dense, rounded crown; it can grow up to 21 metres tall. The erect bole is strongly tapering, around 60cm in diameter at breast height[].
This species is a major source of edible seeds for the native N. Americans who gather them in quantity from the wild and also trade them. The plant is also an excellent fuel and is traditionally used as a source of other foods, medicines and materials.
Pinus edulis has a wide native range and a high population even though there is evidence of some decline due to clearance of pinyon-juniper woodland in favour of pastureland, and extensive recent dieback associated with repeated droughts and pine bark beetle infestations. The plant is classified as 'Least Concern' in the IUCN Red List of Threatened Species(2013)[].

Known Hazards

The wood, sawdust and resins from various species of pine can cause dermatitis in sensitive people[].

Botanical References

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Range

South-western N. America - California to Wyoming, south to Arizona, New Mexico and Texas and into northern Mexico (Chihuahua)

Habitat

Dry mountain slopes, mesas, plateaux, and pinyon-juniper woodland; at elevations from 1,500 - 2,100 metres[]. Eastern foothills of the outer reaches of the Rockies on arid mesas in pure stands or with junipers[].

Properties

Conservation Status	Least Concern
Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Evergreen Tree
Height	15.00 m
Growth Rate	Slow
Pollinators	Wind
Self-fertile	No
Cultivation Status	Wild

Cultivation Details

Pinus edulis is a very cold-hardy plant, able to tolerate temperatures down to around -25°c when fully dormant. It grows in an areas where summers are hot and winters cold, but climatic conditions vary according to elevation and latitude[].
Pine species in general require a sunny position if they are to grow well and, whilst the different species have their own soil preferences, most will thrive in a light well-drained sandy or gravelly loam[, ]. Soils in the wild are commonly thin to sceletal or may be absent altogether, with the trees growing from fissures in the sandstone, limestone, or shale[]. Dislikes poorly drained moorland soils[]. Established plants tolerate drought[]. Succeeds in a hot dry position[]. Prefers an acid soil in full sun[].
A slow-growing but long-lived tree in the wild[, ], it takes about 25 years from seed before it produces seed[]. It then produces good crops every 3 - 4 years[].
The seeds are an important item of food for the local native Americans, it is also sold in local markets of Colorado and New Mexico[, ]. About 450,000 kilos of the seeds are sold in American markets each year[].
The almost globose seed cones are around 35 - 50mm in diameter. They take two growing seasons to mature, opening and shedding their seed whilst still attached to the tree[, ].
This is one of several species of pine that depend upon a mutualistic relationship with a species of bird (in this case Clark's nutcracker, Nucifraga columbiana) to disperse its seed. The birds have powerfull beaks which enable them to extricate the seeds and crack the shells. They store many of the seeds at some distance from the parent plant - some of these seeds never get eaten and can germinate and grow into new trees[].
Trees take about 250 - 350 years to reach full maturity[].
This species is considered by some botanists to be no more than a form of Pinus cembroides, its main difference from that species is that it has leaves in bundles of two whereas Pinus cembroides usually has bundles of three[].
Plants are strongly outbreeding, self-fertilized seed usually grows poorly[]. They hybridize freely with other members of this genus[].
This species is the state tree of New Mexico[].
Plants in this genus are notably susceptible to honey fungus[].

Edible Uses

Seed - raw or cooked[, ]. A slightly resinous flavour, but delicious raw or cooked[, ]. The seed can be ground into a meal and used in stews, making bread, cakes etc and in making nut butter[]. The seed is up to 15mm long[]. Rich in oil, protein[] and thiamine[]. The seed contains about 15% protein[].

The leaves can be brewed into a tea[, ].

Immature female cones - roasted. The soft centre forms a sweet syrupy food[].

Inner bark - cooked. A sweet flavour, it is cut into strips and cooked like spaghetti[]. Inner bark can also be dried, ground into a powder and used as a thickening in soups or can be mixed with cereal flours when making bread etc[].

The pitch from the trunk can be hardened and used as a chewing gum[].

A vanillin flavouring is obtained as a by-product of other resins that are released from the pulpwood[].

Medicinal

Oil of turpentine, obtained from the oleo-resin of all pine trees, is antiseptic, antispasmodic, astringent, diuretic, rubefacient, stimulant and vermifuge[, ]. It is a valuable remedy used internally in the treatment of kidney and bladder complaints and is used both internally and as a rub and steam bath in the treatment of rheumatic affections[]. It is also very beneficial to the respiratory system and so is useful in treating diseases of the mucous membranes and respiratory complaints such as coughs, colds, influenza and TB[].
Applied externally in the form of liniment plasters, poultices, herbal steam baths and inhalers, it is a very beneficial treatment for a variety of skin complaints, wounds, sores, burns, boils etc[].
The heated pitch has been applied to the face to remove facial hair[].

The gum is used as a plaster on cuts and sores[].

An infusion of the leaves has been used as an emetic to cleanse the stomach[]. The leaves have been chewed in the treatment of venereal diseases[]. The leaves have been burnt and the smoke inhaled as a treatment for colds[].

The inner bark is expectorant[].

Agroforestry Uses:

The needles contain a substance called terpene, this is released when rain washes over the needles and it has a negative effect on the germination of some plants, including wheat[].

Other Uses

A tan or green dye is obtained from the needles[].
The gum (resin) has been used, with sumac leaves (Rhus spp) and yellow ochre to make a black dye and ink[]. The sumac leaves are boiled until there is a strong mixture. Whilst the sumac was boiling, the ochre was powdered and roasted. The gum was then added to the ochre and the whole roasted again. As the roasting proceeded, the gum melted and finally the mixture was reduced to a black powder. This was then cooled and thrown into the sumac mixture, forming a rich blue-black fluid that was essentially an ink[].

Oleo-resins are present in the tissues of all species of pines, but these are often not present in sufficient quantity to make their extraction economically worthwhile[]. The resins are obtained by tapping the trunk, or by destructive distillation of the wood[, ]. In general, trees from warmer areas of distribution give the higher yields[].
Oil of Turpentine consists of an average of 20% of the oleo-resin[] and is separated by distillation[, ]. Turpentine has a wide range of uses including as a solvent for waxes etc, for thinning and dissolving varnish and paints, a shoe polish, medicinal etc[, ].
Rosin is also obtained by distillation of pine resin. This is used in paper glue and soap manufacturing, as a constituent of varnishes and paints, and for coating the bows of stringed musical instruments such as violins[, ].
Pitch can also be obtained from the resin and is used for waterproofing, as a wood preservative etc[].

The gum (this almost certainly means the resin[]) is used traditionally in waterproofing baskets, canoes etc, for repairing pottery vessels and in making turquoise mosaic[, ]. It has also been used as a red paint on jars and bowls[]. For waterproofing containers, the gum was melted and poured inside the container. The container was then turned round to ensure the gum came into contact with all parts of the inside. More gum would then be applied to the outside[].
The resin has been used as a glue for fixing turquoise in jewellery[].

The wood is light in weight, soft, not strong, brittle. A timber of reasonable quality but not often available in a good enough form for sawn timber. It is more likely to be used for fencing, mining props etc[, , ].
The wood makes a good fuel, burning with few sparks being thrown out[]. It has a higher than average heat value and burns with a distinctive aroma[]. A charcoal made from the wood is used in smelting[].

Propagation

It is best to sow the seed in individual pots in a cold frame as soon as it is ripe if this is possible otherwise in late winter. A short stratification of 6 weeks at 4°c can improve the germination of stored seed[]. Plant seedlings out into their permanent positions as soon as possible and protect them for their first winter or two[]. Plants have a very sparse root system and the sooner they are planted into their permanent positions the better they will grow[]. Trees should be planted into their permanent positions when they are quite small, between 30 and 90cm[]. We actually plant them out when they are about 5 - 10cm tall. So long as they are given a very good weed-excluding mulch they establish very well[]. Larger trees will check badly and hardly put on any growth for several years. This also badly affects root development and wind resistance[].
Cuttings. This method only works when taken from very young trees less than 10 years old. Use single leaf fascicles with the base of the short shoot. Disbudding the shoots some weeks before taking the cuttings can help. Cuttings are normally slow to grow away[].