Pseudotsuga japonica 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Plantae Tracheophyta Pinopsida Pinales Pinaceae

Scientific Name: Pseudotsuga japonica (Shiras.) Beissn.
Common Name(s):
English Japanese Douglas-fir
Tsuga japonica Shiras.
Taxonomic Source(s): Farjon, A. 2010. A Handbook of the World's Conifers. Koninklijke Brill, Leiden.

Assessment Information [top]

Red List Category & Criteria: Endangered C2a(i) ver 3.1
Year Published: 2013
Date Assessed: 2010-12-14
Assessor(s): Katsuki, T., Luscombe, D & Farjon, A.
Reviewer(s): Thomas, P. & Yahara, T.
This is a very rare species, with only small and scattered subpopulations of very slow growing trees. The total population is not larger than 2,500 trees, there are no subpopulations exceeding 250 mature trees and there is a continuing decline. On this basis it qualifies for Endangered under the C criterion.
Previously published Red List assessments:

Geographic Range [top]

Range Description:Japan: W Honshu (Chugoku District), Shikoku. E H. Wilson (1916) reported it as very rare in Kyushu, but its occurrence there has not been confirmed later.
Countries occurrence:
Japan (Shikoku)
Additional data:
Estimated area of occupancy (AOO) - km2:2000
Lower elevation limit (metres):500
Upper elevation limit (metres):1000
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:The population is declining (T. Yahara pers. comm)
Current Population Trend:Decreasing
Additional data:
Number of mature individuals:2000Continuing decline of mature individuals:Yes
Continuing decline in subpopulations:No
Extreme fluctuations in subpopulations:NoAll individuals in one subpopulation:No

Habitat and Ecology [top]

Habitat and Ecology:Pseudotsuga japonica occurs at elevations between 500 m and 650 m a.s.l. on Shikoku; Wilson (1916) reports it from about 1,000 m on the same island. It is rare and scattered in sheltered valleys and steep ravines, growing on old volcanic rock. The climate is warm temperate, moist, with annual precipitation between 1,000 and 2,000 mm. It is locally a (major) constituent of mixed conifer-broad-leaved forests, with Tsuga sieboldii usually as the dominant species. Other conifers are Abies firma, Chamaecyparis obtusa, Torreya nucifera and Cryptomeria japonica, broad-leaved trees are e.g. Quercus salicina, Q. sessilifolia, Cleyera japonica, and Illicium religiosum (small tree), common shrubs are Eurya japonica, Pieris japonica, Rhododendron serpyllifolium, and Thea japonica. As in China, in Japan the genus, represented by a single species, is a minor constituent of mixed forests
Continuing decline in area, extent and/or quality of habitat:Yes
Generation Length (years):50

Use and Trade [top]

Use and Trade: Japanese Douglas-fir is of minor importance as a timber tree due to its rarity and modest size, although veteran trees can attain substantial trunk diameters. The wood is used for construction of traditional buildings and gateways and for furniture. In Japan, it may be seen planted in some parks and traditional gardens, outside its country of origin it is a rare tree only present in some arboreta. This species was collected by Ernest H. Wilson in 1914 and introduced via the Arnold Arboretum of Harvard University to the USA. In Europe it seems to have arrived a few years earlier, perhaps a little after 1900 in Germany. It grows slowly in cultivation and seems to remain a small tree with a rather limited life span.

Threats [top]

Major Threat(s): The main  threat has been the conversion of habitat to plantation forestry and other uses. Regeneration is poor and older trees are declining. The total population of this species in Japan is estimated to be ca. 2,000 mature trees and is considered to be continuously declining.

Conservation Actions [top]

Conservation Actions: The species is known from at least one protected area.

Citation: Katsuki, T., Luscombe, D & Farjon, A. 2013. Pseudotsuga japonica. The IUCN Red List of Threatened Species 2013: e.T31291A2803646. . Downloaded on 18 June 2018.
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