Photograph of type specimen, from Craib (1919).
Pseudotsuga forrestii
澜沧黄杉 lan cang huang shan (Wu and Raven 1999), Lancang Douglas-fir.
Syn: P. sinensis var. forrestii (Craib) Silba 1990 (Wu and Raven 1999); type G. Forrest No. 13,003, Mekong Valley, Yunnan, latitude 27.667°N, elev. 10,000 ft, August 1914. See the discussion in Pseudotsuga regarding the rationale for treating this taxon at species rank. In particular, it is in a clade sister to P. sinensis and P. japonica.
"Trees to 40 m tall; trunk to 80 cm d.b.h.; bark dark brown-gray, rough, deeply fissured longitudinally; branchlets initially pale yellow or greenish yellow, becoming reddish brown when dry, light brown or brownish gray in 2nd or 3rd year, glabrous or pubescent. Leaves pectinately arranged, subsessile, linear, 2.8-5.5 cm × 1.3-1.8(-2) mm, base cuneate, apex emarginate. Seed cones ovoid, 5-8 × 4-5.5 cm. Seed scales at middle of cones suborbicular or rhombic-orbicular, (2.5-)2.7-3.5 × 3-3.6(-4) cm, glabrous abaxially, base cuneate-orbicular. Bracts obviously longer than seed scales, reflexed, cusp lanceolate, 6-12 mm, lateral lobes narrowly triangular, ca. 3 mm. Seeds light brown, irregularly dark spotted, triangular-ovoid, slightly depressed, glabrous adaxially; wing obliquely ovate. Seed maturity Oct." (Wu and Raven 1999).
This species has the longest needles of any Pseudotsuga, up to 5.5 cm long, and generally also has longer cones compared to P. sinensis (Debreczy and Rácz 2011). In his description, Craib (1919) noted these things, and also stated that the cone bracts are much longer than in P. sinensis, as well as going into some detail regarding differences in leaf anatomy between the two taxa.
China: Xizang, Sichuan, and Yunnan, where it is found mainly in the Hengduan Shan at 2400-3300 m elevation, often in association with Pinus armandii, P. yunnanensis, and Taxus wallichiana (Debreczy and Rácz 2011).
Pseudotsuga of Asia; P. forrestii in blue. Distribution data from GBIF, 2021.02.22.
Wu and Raven (1999) state that this is a vulnerable species. The IUCN assessment overestimates the species' distribution, treating it as synonymous with T. sinensis var. sinensis. A current (2023) assessment would likely find it "endangered" due to low area of occupancy and decline linked to grazing and timber exploitation, which are factors of decline for other conifers in this geographic range.
The timber is used for construction, bridge building, vehicles, and furniture. The species is also grown for afforestation (Wu and Raven 1999).
The epithet refers to George Forrest (1873-1932), who collected it in 1914 in mixed forests in the upper Mekong watershed (Bean 1988). Forrest made five collecting trips to China, supported by the nurseryman A. K. Bulley, and introduced many new species to science. He is also remembered in Abies forrestii and Tsuga forrestii.
Bean, W. J. 1988. Trees and Shrubs Hardy in the British Isles, 8th ed. London: John Murray.
Last Modified 2023-02-26
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