Scientific name: Pinus hartwegii Lindley 1839
Synonyms: Pinus aculcensis Roezl, Pinus amecaensis Roezl, Pinus atrovirens Roezl ex Gordon, Pinus clamaensis Carrière, Pinus corrugata Roezl ex Gordon, Pinus donnell-smithii Mast., Pinus ehrenbergii Endl., Pinus endlicheriana Roezl, Pinus frondosa Roezl ex Gordon, Pinus geitneri Roezl ex Gordon, Pinus iztacihuatlii Roezl, Pinus krelagii Roezl ex Gordon, Pinus lindleyana Loudon ex Gordon, Pinus lowii Roezl, Pinus montezumae Gordon, Pinus montezumae var. hartwegii (Lindl.) Shaw, Pinus montezumae subsp. hartwegii (Lindl.) Engelm., Pinus montezumae var. lindleyana (Loudon ex Gordon) Parl., Pinus montezumae var. rudis (Endl.) Shaw, Pinus northumberlandiana Roezl, Pinus papeleuii Roezl, Pinus resinosa Roezl, Pinus robusta Roezl, Pinus roezlii Carrière, Pinus rudis Endl., Pinus scoparia Roezl, Pinus standishii Roezl, Pinus suffruticosa Roezl. ex Carrière, Pinus tlamacaensis Roezl ex Gordon, Pinus wilsonii Roezl
Common names: Hartweg pine, Hartweg's pine, Mexican mountain pine, Mesoamerican subalpine pine (English), Ocote, Pino de las Alturas, Pino de México (Spanish)
Description
Tree to 30 m tall, with trunk to 0.7(-1) m in diameter, shorter at higher elevations and shrubby at the alpine tree line. Bark grayish brown, thick, divided into irregular, scaly or rough plates of various sizes on different trees. Crown dense, conical at first, broadening and rounding with age, sometimes becoming almost spherical, with numerous gently rising to horizontal branches densely clothed with foliage at the tips. Twigs dark reddish brown with a thin coating of grayish was at first, rough with the bases of scale leaves, hairless. Buds 2-3 cm long, not resinous. Needles in bundles of (three or) four or five (to seven), each needle (6-)10-17(-25) cm long, thick and stiff, microscopically toothed along the edges, lasting 2-3 years, light to dark green or sometimes a little waxy bluish green. Individual needles with numerous lines of stomates on all three faces, and (2-)4-8(-11) resin canals surrounding the two-stranded midvein midway between it and the leaf surface. Sheath 20-30(-40) mm long at first, weathering to 10-20 mm and persisting and falling with the bundle. Pollen cones 12-25 mm long, reddish brown. Seed cones (6-)8-12(-15) cm long, egg-shaped with a flat base, often slightly asymmetrical, with 120-220 seed scales, purplish green before maturity, ripening dark brown to black, opening widely to release the seeds and persisting a while before falling off the very short stalk to 10 mm and leaving a few basal scales behind. Seed scales square-sided with a bluntly triangular tip, the exposed face horizontally diamond-shaped, thin and low but crossed by a horizontal keel topped by a diamond-shaped umbo often bearing a stout prickle. Seed body 5-7 mm long, the clasping wing another (12-)15-20(-23) mm longer.
The species name honors Karl Hartweg (1812 - 1871), the German botanist who collected the type specimen during his extensive travels in Mexico.
Mountains of western Honduras, southern Guatemala, and northward discontinuously through southern and central Mexico to southern Chihuahua, southern Coahuila, and central Nuevo León. Forming pure open forests and thickets or mixed with other subalpine and upper montane species; 2,300-)2,700-4,000(-4,300) m.
Conservation Status
Red List Category & Criteria: Least Concern
This species has a very large extent of occurrence and is mostly confined to the highest altitude pine forests, where its exploitation is limited. It is therefore assessed as Least Concern.
Pinus hartwegii is the typical high-altitude pine of Mexico and Guatemala, where it often forms extensive, monotypic pine forests up to the tree line on high, isolated volcanoes or summits of mountain ranges. In Honduras it is rare, of limited extent and usually found with Abies guatemalensis, Cupressus lusitanica, Juniperus standleyi, Quercus spp., Dendropanax lempirianus, Drymis granadensis, a ground cover of Ericaceae, Lycopodiaceae, and epiphytic Bromeliaceae in a cool cloud forest type usually between 2,700-2,850 m on the highest mountain summits. Similar forests occur in Guatemala and the southern states of Mexico, but there extensive pine forests predominate, in which Pinus hartwegii increasingly dominates with rising altitude. Its altitudinal range in Guatemala and Mexico is similar: (2,300-)2,700-4,000(-4,300) m a.s.l. At lower elevations it is often mixed with Pinus montezumae, with which it is closely related, and with other pines depending on the geographical area. Soils are both from volcanic and granitic rock, of various depths, but often poor in nutrients. Climatically there are considerable differences congruent with latitude/altitude gradients, with heavy frost and snow during several months and often high winds near the tree lines of the high volcanoes in Central Mexico.
May form large, monotypic forests. The population trend is stable. With global warming, the habitats of this species are becoming less cold and this is resulting in the trees becoming more stressed, weakening the species and allowing attacks of pests such as bark beetles (Dendroctonus spp.).
Pinus hartwegii has fairly dense, but resinous wood. It is exploited as a timber tree where stands are extensive and accessible, but due to high altitude and consequent lack of infrastructure (access roads) many forests remain virtually untouched today. Its wood is used as round wood for posts and sawn for construction or railway sleepers, while it is also pulped for the paper industry. Despite its hardiness, originating from very high altitudes, it is very rare in cultivation, in some instances under its taxonomic synonym Pinus rudis.
This widespread species is present in many protected areas, including several national parks.
Cultivars
Not known
References
- Farjon, A. (2010). A Handbook of the World's Conifers. Koninklijke Brill, Leiden.
- Eckenwalder, J.E. (2009) Conifers of the World: The Complete Reference. Timber Press, Portland.
- IUCN Red List of Threatened Species, International Union for Conservation of Nature and Natural Resources. Cambridge, UK /Gland, Switzerland
Copyright © Aljos Farjon, James E. Eckenwalder, IUCN, Conifers Garden. All rights reserved.