Calocedrus rupestris Aver.,T.H.Nguyên & P.K.Lôc

Cupressaceae

Calocedrus rupestris was first described in 2008 from Việt Nam: prior to this Calocedrus trees occurring on limestone karst  were wrongly identified as Calocedrus macrolepis.  In 2011 C. rupestris was discovered in Guangxi. Threats include selective logging for timber, deforestation and forest degradation.

Associated Names:

Description

A recent molecular study using ITS sequences suggest that C. rupestris shows insufficient variation to be considered distinct from C. macrolepis at the species level. However, in our view, it would be premature to adopt this approach until further research using other genes is undertaken.

Distribution

In Việt Nam it is recorded from the karst limestone areas of Bắc Kạn, Cao Bằng, Hà Giang, Hoà Bình, Nghệ An, Quảng Bình, Sơn La. It may occur in adjoining provinces of Lao PDR that share the same limestone geological formations (Sơn La/Houaphan, Quảng Bình/Khammouan and Savannakhet). It has also recently been reported from Guangxi in China (Nong et al, 2011).

This species is rare in most provinces although it may be locally common in specific localities. The total subpopulation in Việt Nam is estimated to be less than 2500 mature individuals with the largest subpopulation in Quảng Bình. In Guangxi, the subpopulation is estimated to be about 2100 individuals. It is uncertain how many of these are mature trees.

Habitat and Ecology

The species grows on rocky limestone ridges and steep slopes. Associated conifers vary according to location: Pseudotsuga sinensis, Keteleeria and Pinus sp. in the northern localities; Dacrycarpus imbricatus and Dacrydium elatum in the southern localities (Quảng Bình). Seedlings and regeneration of C. rupestris is rare and hence recruitment is poor.

Human Uses

This species is frequently exploited for its valuable timber which may be used for construction, furniture and fine crafts. Resin is also used.

Conservation Status

Global status

Endangered A2cd

Global rationale

The proposed status of Endangered is based on an estimated decline in the total population of more than 50%. This is also based on the assumption that the species is primarily distributed in Việt Nam. Previous assessments have also used Criterion C (population < 2500). With its discovery in Guangxi, it no longer meets that criterion. If additional subpopulations are found in China, then a new assessment would be required.

Global threats

C. rupestris is threatened throughout its range by selective logging for timber, general deforestation and forest degradation.

Conservation Actions

The species has been recorded from some protected areas in Việt Nam and China: Phong Nha-Kẻ Bàng National Park (Quảng Bình) and Bat Dai Son Nature Reserve (Hậ Giang) and Mulun Nature Reserve (Guangxi)