Calocedrus macrolepis Kurz

Cupressaceae

A widespread species that has been exploited for timber and resin. Difficulties in estimating the extent of its decline and a lack of information about its staus is some parts of its range have resulted in an assessment of Near Threatened.

Description

Taxonomic Notes

On the IUCN Redlist, Calocedrus formosana and C. rupestris are treated as a distinct species, rather than as varieties or subspecies of C. macrolepis. Phylogenetic work using ITS sequences indicates that the Taiwanese C. formosana is distinct from the other two taxa which are much more closely related and there may be some argument for treating C. rupestris as a variety rather than a distinct species (Chen et al. 2009; Long et al. 2011). STudies to date have only included a limited number of samples from a small part of its range and further work is necessary before changes are made.

Distribution

Calocedrus macrolepis has a wide distribution in southern China and SE Asia. In China it is recorded from Guangxi (Jingxi Xian), Guizhou, Hainan Island and Yunnan. Its complete distribution in Myanmar is uncertain while in Thailand it is only known from a limited area in the northeast. In Lao PDR it is currently known from several provinces adjoining the Vietnamese border (Thomas et al. 2007). In Viet Nam it is known from the southern highlands, especially in Lam Dong Province. Previously it was thought to be more widespread but populations occurring in limestone karst areas of central and northern Viet Nam have recently been identified as a separate species, Calocedrus rupestris (Averyanov et al. 2008).

In China it has been estimated that the population comprises about 200,000 plants although it is uncertain if this estimate includes re-afforested areas. The major subpopulations are found in Yunnan province. In Viet Nam and Lao PDR subpopulations are small and localized and have been severely reduced by logging and conversion of forest to agriculture.

Habitat and Ecology

In China it occurs in montane mixed evergreen conifer-broad-leaved forest dominated by Fagaceae and with scattered conifers, e.g. Cunninghamia, Keteleeria and Pinus; also in rocky places and much planted in roadsides and field margins. The altitudinal range is from ca. 600 m to 2,000 m a.s.l. Outside of China it generally occurs from 800 to 1500 m a.s.l. in evergreen hill forests. In Viet Nam and Lao PDR it occurs with Dacrycarpus imbricatus, Dacrydium elatum and Keteleeria evelyniana. It is often found along watercourses.

Human Uses

In China this species is considered suitable for afforestation of deforested lands in its native area because of its easy germination (also grows from cuttings) and light-demanding properties combined with rapid growth. Its wood has good properties, e.g. durability, but trees tend to be much branched especially when grown in open vegetation. In Viet Nam and Lao PDR the timber and resin are highly valued for high value furniture and incense.

Conservation Status

Global Status and Rationale

Near Threatened (VU A2cd)

Calocedrus macrolepis has a wide but fragmented distribution in southern China, Myanmar, Thailand, Lao PDR and Viet Nam. Its extent of occurrence and area of occupancy are above the maximum IUCN thresholds. The majority of the subpopulations are thought to be in Yunnan; most of these show some signs of regeneration. However, it is uncertain how many of these subpopulations represent wild occurrences. Although there has been range wide exploitation in the past and although there is an ongoing decline in Viet Nam and Lao PDR, it is uncertain if the total decline is sufficient for even a global listing of Vulnerable under the IUCN’s criterion A. In the absence of such information an assessment of Near Threatened (nearly meeting VU A2cd) is appropriate .

Global Threats

The major threat has been overexploitation for its valuable timber throughout its range. In southern Viet Nam and Lao PDR it has also been, and continues to be threatened by forest fragmentation, forest fire and conversion of its habitat to agricultural use. In China it has been assessed as nationally Vulnerable under the IUCN A2 criterion; in Viet Nam it has been assessed as Endangered under a range of criteria. No formal assessment has been undertaken in Lao PDR, Myanmar or Thailand.

Conservation Actions

In China, most plants occur near temples and so are protected. In other parts of its range it occurs in many protected areas such as Nakai Nam Theun National Biodiversity Area (Lao PDR), Bi Doup National Park (Viet Nam) and Phu Kradung in Thailand.
It has legal protection in China under the National List (2nd degree of protection). The Government of China has also imposed a recent ban on all logging. In Viet Nam it is included on the List of Rare and Precious Flora which restricts its exploitation. In Lao PDR, Myanmar and Thailand it has no formal protection.
Further research is required to establish its distribution and status in Myanmar and in the central Annamite ranges of Viet Nam and Lao PDR