Thuja sutchuenensis

Taxonomy

Assessment Information

Geographic Range

Population

Habitat and Ecology

Threats

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Taxonomy [top]

Kingdom	Phylum	Class	Order	Family
PLANTAE	TRACHEOPHYTA	CONIFEROPSIDA	CONIFERALES	CUPRESSACEAE

Scientific Name:	Thuja sutchuenensis
Species Authority:	Franchet

Assessment Information [top]

Red List Category & Criteria:

Critically Endangered B1ab(ii,iii,v) ver 3.1

Year Published:

2003

Assessor/s:

Xiang Qiaoping, Farjon, A., Li Zhenyu, Fu Likuo & Liu Zhengyu (Conifer Specialist Group)

Reviewer/s:

Farjon, A. & Hilton-Taylor, C. (Conifer Red List Authority)

Contributor/s:

Justification:
Was listed as Extinct in the Wild (Oldfield et al. 1998) but was rediscovered in October 1999 by a regional team of botanists, not far from (or perhaps at) the locality where P. G. Farges had collected the only known specimens between 1892 and 1900. The team found individual trees growing scattered on cliffs and ridges of the deeply cleft mountain. There were no large trees, with most being small or even shrub-like because of their locations at higher altitudes and on exposed ridges. Seedlings are scarce. The more accessible trees have mostly been felled for use in home building and for making various household products. The species may also have gone through a genetic bottleneck and be facing problems of inbreeding depression.

History:

1998	–	Extinct in the Wild (Oldfield et al. 1998)
1998	–	Extinct in the Wild
1997	–	Endangered (Walter and Gillett 1998)

Geographic Range [top]

Range Description:	In 1892, the French missionary P.G. Farges was the first westerner to conduct a botanical survey in Chengkou county, Chongqing Municipality (formerly eastern Sichuan Province), in central China. Among the many new species discovered by Farges, was Thuja sutchuenensis. After his first collection, Farges returned a number of times to the area up until 1900 and collected additional specimens of this species. Later in the twentieth century, a number of botanical collecting trips were made to Chengkou by Chinese botanists. Some trips were specifically made to find T. sutchuenensis. However, nothing was found and it therefore remained known only from specimens collected by Farges and lodged in various European herbaria, although it was said to be in cultivation in China. Nothing was known about the habitat in which the species had been found, and it was not even certain that the species had been collected in the wild, as only the town of Chengkou was mentioned as its locality. As a result, the species was widely regarded to be Extinct in the Wild, and was considered to be the only conifer to have disappeared from nature in historic times (Farjon and Page 1999). In October 1999, an expedition in search of rare and endangered plants of Chongqing Municipality organized by a local forest bureau carried out a thorough investigation of Chenkou county. In the Dabashan Mountains they discovered a wild population of Thuja sutchuenensis.
Countries:	Native: China (Chongqing)
Range Map:	Click here to open the map viewer and explore range.

Population [top]

Population Trend:	Decreasing

Population Trend:

Decreasing

Habitat and Ecology [top]

Habitat and Ecology:	Occurs on steep slopes and ridges of a limestone formation at altitudes between 800 and 2,100 m (but mostly between 1,000 and 1,500 m). The population grows on ridges and mountain summits where the soil is shallow and even grows in rock crevices, devoid of soil. The surrounding vegetation is largely deciduous broad-leaved temperate forest.
Systems:	Terrestrial

Threats [top]

Major Threat(s):	The fragrant and rot-resistant wood of Thuja sutchuenensis is a very desirable resource. The wood is soft, light and very easily worked. It is used for applications requiring decay resistance by local people, e.g., home construction, production of shingles, application for funeral services, etc. As a result most of the easily accessible trees have been chopped down, leaving only a single very remote and largely inaccessible subpopulation. Inbreeding among the remaining individuals is potentially a problem which requires further investigation. Plant diseases caused by microorganisms have also been observed, but it is not clear what impact, if any, these may have.

Major Threat(s):

The fragrant and rot-resistant wood of Thuja sutchuenensis is a very desirable resource. The wood is soft, light and very easily worked. It is used for applications requiring decay resistance by local people, e.g., home construction, production of shingles, application for funeral services, etc. As a result most of the easily accessible trees have been chopped down, leaving only a single very remote and largely inaccessible subpopulation.

Inbreeding among the remaining individuals is potentially a problem which requires further investigation. Plant diseases caused by microorganisms have also been observed, but it is not clear what impact, if any, these may have.

Citation:	Xiang Qiaoping, Farjon, A., Li Zhenyu, Fu Likuo & Liu Zhengyu (Conifer Specialist Group) 2003. Thuja sutchuenensis. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 20 June 2013.
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