Common Name: Smooth-Leaf Pine

General Information

Pinus leiophylla is an evergreen tree with an open rounded or flat-topped crown; it can grow 15 - 35 metres tall. The straight, cylindrical bole can be 20 - 85cm in diameter, usually with a single round bole that is often clear of branches for 60% of the tree's height[, , ]
Mainly valued for its resin, which is exploited commercially, the tree is also logged commercially as a timber and has a range of medicinal uses. It has been planted in various parts of the world, especially in Africa, as a plantation forestry tree[]. The variety chihuahuana is less exploited for timber, but is an equally prolific producer of resin[].
Along with many other species of pine in the Sierra Madre Occidental of Mexico, Pinus leiophylla has been heavily exploited for timber since the latter half of the 20th century. This species has a very wide distribution, however, and is still common in many areas and so 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

, ,

Range

Southern N. America - southeastern Arizona, southwestern New Mexico, southwards to southern Mexico (Oaxaca)

Habitat

Pine and pine-oak forest in montane regions; at elevations from 1,500 to 3,300 metres[, ], usually as scattered individuals in pine forests[].

Properties

Conservation Status	Least Concern
Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Evergreen Tree
Height	20.00 m
Growth Rate	Medium
Pollinators	Wind
Self-fertile	No
Cultivation Status	Cultivated, Wild

Cultivation Details

Pinus leiophylla is a plant of higher elevations in the tropics and subtropics of Mexico, where it is found at elevations of 1,800 - 2,100 metres. It is not very cold-hardy, being able to withstand short periods with temperatures falling to around freezing, though the variety chihuahuana has a more northerly range and is somewhat more cold tolerant[]. Annual precipitation varies greatly with locality and elevation, from a low of around. 700 mm to 1,950 mm. In the north and at high elevations, frost and snow are common in winter[]..
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[, ]. Found in the wild on deep, well drained soils derived from various, but usually volcanic or metamorphic rock[]. Dislikes poorly drained moorland soils[]. Established plants tolerate drought[].
Unlike virtually all other members of this genus, this tree can produce adventitious shoots from stumps or the trunk, allowing it to regrow after a low intensity fire and to withstand limited coppicing[82.1212]. The shoots often do not last, however[].
Plants are strongly outbreeding, self-fertilized seed usually grows poorly[]. They hybridize freely with other members of this genus[].
The seed cones can be 4 - 8cm long and 3 - 5cm wide.They take three growing seasons to reach maturity, opening and shedding their seed in the autumn whilst still attached to the tree[, , , ].
Plants in this genus are notably susceptible to honey fungus[].

Edible Uses

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

The seeds of all Pinus species are more or less edible, and some are of good size and make very tasty and nutritious foods, often eaten in quantitiy. Others can be less desireable, either having a strongly resinous flavour, being bitter or, more commonly, rather too small and fiddly to make it very worthwhle even trying to eat them,
We have no specific information of the desireability of this species, though they are rather small (the size given includes the shell)[].
The dark grey-brown, ovoid seeds are 3 - 5mm long[].

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 most common use of this species is in the treatment of coughs, a tea being made from the bark[]. It is also used as an expectorant, and in the treatment of acute bronchitis[].
The plant is also used in the treatment of rheumatism, dermatitis, to heal wounds and as a diuretic and an antiseptic of the urinary tract[].

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[].

This plant is an important source of turpentine, obtained from the oleo-resins in the tissues of the tree[]. The resins are obtained by tapping the trunk, or by destructive distillation of the wood[, ].
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 wood is light in weight, coarse-grained, soft, not strong, durable[]. Due to its high resin content it does not provide high quality wood The wood is used in heavy construction and for crates and boxes[].
The wood has a specific gravity of 0.44 to 0.51, and is relatively dense, heavy, hard, and very resinous with a pale brown heartwood[].

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[].