Mature trees in habitat, El Ranchito en Bocoyna, Chihuahua [Mauricio Mantilla Blandon (email 2006.06.30)]

Sapling in habitat, El Ranchito en Bocoyna, Chihuahua [Mauricio Mantilla Blandon (email 2006.06.30)]

Foliage from a tree in habitat, El Ranchito en Bocoyna, Chihuahua [Mauricio Mantilla Blandon (email 2006.06.30)]

Cone from a tree in habitat, El Ranchito en Bocoyna, Chihuahua [Mauricio Mantilla Blandon (email 2006.06.30)]

Distribution map (USGS 1999.

Picea chihuahuana

Martínez 1942

Common Names

Chihuahua spruce (Farjon 1990). Pinabete de Chihuahua (Mexican Spanish).

Taxonomic notes

Picea martinezii Patterson is sometimes considered synonymous with it (Farjon 1990), but proved clearly distinct on detailed analysis, "justifying the retention of P. martinezii as a separate species" (Taylor et al. 1994).

Description

A tree to 25-35 m tall and 45-70 cm dbh, with pale grey furrowed and scaling bark. Crown narrow-conic, open with few long level branches among more numerous very short branches. Shoots stout, pale buff. Leaves blue-green, matt with conspicuous stomatal lines, 17-23 mm long, rhombic to slightly flattened in cross-section, exceedingly sharp (readily drawing blood when shoots grasped!) with a long spine tip. Cones green ripening orange-brown, cylindrical, 7-12 cm long, 4-5 cm broad when open with tightly packed or even congested scales 18-23 mm long and 14-20 mm wide, apex truncated, almost square-ended. Seed 3.5-4 mm, black, with a 10-12 mm wing. (Martínez 1953, Gordon 1968, Nienstaedt 1983, Taylor et al. 1994, and cones in M. P. Frankis collection).

See P. martinezii for differences from that species.

Range

Mexico: SW Chihuahua, W Durango, at 2300-(?)3200 m altitude (Gordon 1968). Each of the 25 populations consists of less than 100 to 350 mature trees (Farjon 1990). USDA hardiness zone 8.

Big Tree

Oldest

Dendrochronology

A fire history study is described by Fulé et al. (2005).

Ethnobotany

Observations

The Chihuahua/Durango populations are near El Salto in the Sierra Madre Occidental (Farjon 1990). A preserve has recently been set aside at the Tutuaca reserve in the Sierra Madre Occidental of western Chihuahua (Fulé et al. 2005), and that also sounds like a promising place to find it.

Remarks

"A species known from about 25 sites, containing a few to several hundred trees, often in canyons or on moist north-facing scree slopes. Regeneration is poor and inadequate. A continued decline in the population, especially of seeding trees, is expected" (World Conservation Monitoring Centre - Trees). It is also listed as endangered by the Mexican government (NOM-ECOL-059-94).

The foliage is superficially similar to Picea pungens, but the cone is markedly different and shows its alliances are to other species; the most similar in cone are P. martinezii and some species in E Asia, notably P. torano.