Common Names

Mexican white pine, pinabete, acalocote (Perry 1991).

Taxonomic notes

Syn.: Pinus don-pedrii Roezl 1857, Pinus hamata Roezl 1857, Pinus loudoniana Gordon var. don-pedrii (Roezl) Carrière 1867, Pinus ayacahuite Ehrenb. ex Schltdl. var. oaxacana Silba 1990 (Farjon 1998).

Description

Tree, to 35-40(-50?) m tall and 200 cm dbh. Crowns of old trees are open and irregular with horizontal to drooping branches. Crowns of young trees are conical with whorled branches. Bark thin, ash-grey, smooth; becoming rough, grey-brown, scaly, divided into small rectangular plates. Leaves 5 per fascicle (very rarely 6), slender, flexible, (8-)10-15(-18) cm × 0.7-1.0 mm, abaxial surface bright green, adaxial surface glaucous with stoma, margins serrate with minute, widely spaced teeth; stomata only on ventral surfaces; resin canals 2-4(5-6), external; fibrovascular bundle single; sheaths pale brown and early deciduous. Immature cones 1-4, erect on stout peduncles 10-15 mm long; scales thin, wide, without prickle. Mature cones almost cylindrical, tapering toward apex, pendent, slightly curved, (10-)15-40 cm × 7-15 cm when open, yellow-brown, resinous; ripening in the fall and soon deciduous, the 1-3 cm long peduncle falling with the cone. Cone scales 100-120, thin, narrow, flexible, 5-7 cm long, apophyses elongate, apex rounded to obtuse, generally reflexed and curled; umbo terminal without a prickle and nearly always resinous. Seeds 2 per scale, light brown with darker spots, 8-10 × 6-8 mm adnate 20-35 × 8-12 mm wing. Cotyledons usually 11-13 (7-8 in Guatemalan specimens). Wood soft, cream-white, light, not very resinous. Pollen dispersal, in south-central Mexico, typically in May (Perry 1991, Farjon and Styles 1997).

Range

El Salvador, Honduras, Guatemala, and Mexico: Hidalgo, Puebla, Veracruz, Tlaxcala, México, Morelos, Michoacán, Guerrero, Oaxaca, and Chiapas, at (1500-)1900-3200(-3600) m elevation. Typically grows as an emergent in mixed montane forest, often in small groves in locally mesic sites such as riparian areas, typically on well-drained soils (Farjon and Styles 1997). The area where it was formerly described in El Salvador has been intensively exploited for firewood and P. ayacahuite may have now been extirpated from El Salvador (Perry 1991).

Big Tree

Oldest

Dendrochronology

Ethnobotany

Observations

I have found it along Highway 175, the highway from Oaxaca city to Tuxtepec, Oaxaca. This is one of the best drives in the world if you like either driving or natural history; I have provided details HERE, and Perry (1991) also describes this route. P. ayacahuite is fairly common above about 2,500 m elevation.

Totonicapán forest in Guatemala harbors the largest and best-conserved stand of Pinus ayacahuite in Guatemala (ParksWatch 2004). Perry (1991) also suggests a visit to the area around kilometer 168 on Highway CA-1 west of Guatemala City, elev. 3,000 m, where trees over 40 m tall occur in an area locally called "Alaska."

In Honduras, it grows on the upper slopes of Cerro Santa Bárbara (2,800 m) and Cerro Celaque (2,900 m); a reliable guide is necessary to locate the trees (Perry 1991).

Remarks

In Oaxaca, Chiapas and Guatemala, this species is a host to the dwarf mistletoe Arceuthobium guatemalense (Hawksworth and Wiens 1996).

See Also