Chamaecyparis hodginsii

(Dunn) Rushforth 2007

Common names

Po mu (Vietnamese) (FIPI 1996).

Taxonomic notes

Type: China, Yunnan, near border with Vietnam (Farjon 2005). Synonyms: Cupressus hodginsii Dunn 1908; Fokienia kawaii Hayata 1917, nom. illeg.; Fokienia maclurei Merrill 1922; Fokienia hodginsii (Dunn) A. Henry et H.H. Thomas 1911; Fokienia hodginsii (Dunn) A. Henry et H.H. Thomas var. kawaii (Hayata) Silba 2000. In particular, this species is still referred to in most current sources as Fokienia hodginsii. However, Gadek et al. (2000) and Little et al. (2004) both present molecular data showing it as nested within Chamaecyparis. Rushforth (2007) presents a fairly intricate argument based mostly on cone morphology and development to place it within Chamaecyparis, and a molecular analysis by Mao et al. (2010) also places it within Chamaecyparis.

Description

An evergreen tree to 25-35 m tall with dbh up to 200 cm, bole straight, crown pyramidal. Bark brown grey, peeling off when young, later longitudinally fissured, aromatic. Leaves scale-like, arranged in flattened tripinnate branchlet systems, the pinnae disposed in one plane like a Thuja , the branchlets tapering above. Leaves on adult trees arising in whorls of 4 at the same level, sub-acute, about 2 mm long, the lateral leaves ovate, compressed, with white stomatal depressions on their ventral surfaces, facial leaves oblanceolate with a triangular apex, furrowed above. Internodes longer on older branchlets, the leaves rising at different levels in alternately opposite pairs. Leaves on young plants larger, about 8 mm long with spine-like points. Male cones oval to cylindrical, axillary, about 2.5 mm long, with 3-5 pairs of scales. Female cones resemble those of other Chamaecyparis species, ripening in the second year, globose or sub-globose, about 25 mm long, 22 mm wide, shortly stalked, composed of 5-8 pairs of scales, each with a central spine or short process. Seeds 2 on each fertile scale, about 4 mm long, angular, pointed, with 2 large resin blisters on the upper and lower surface; wings lateral, very unequal (Dallimore et al. 1967, FIPI 1996).

Distribution and Ecology

E China: Zhejiang, Fujian, Guizhou, Yunnan (Dallimore et al. 1967); and Vietnam: Dac Lac, Gia Lai, Ha Bac, Ha Giang, Ha Tinh, Hoa Binh, Kon Tum, Lai Chau, Lam Dong, Lao Cai, Nghe An, Son La, Thanh Hoa, Tuyen Quang, Vinh Phu, and Yen Bai (FIPI 1996). Hardy to Zone 8 (cold hardiness limit between -12.1°C and -6.7°C) (Bannister and Neuner 2001).

It is a shade intolerant species, well adapted to mild climates with abundant rainfall, occurring naturally on humid soils in high mountain areas, slopes or flats. In Vietnam it is found at elevations above 900 m on granite or limestone mountains, forming pure stands or mixed with Dacrydium elatum, Pinus dalatensis and other broad-leaved tree species of the families Fagaceae, Lauraceae and Magnoliaceae. Good natural regeneration occurs in open areas, e.g. along streams, at forest edges, and in clearings in young forests (FIPI 1996).

Listed as threatened/endangered in Vietnam by the WCMC (2001). It must be strictly protected in Nature Reserves such as Pu Mat (Nghe An), Vu Quang (Ha Tinh) and Bi Doup (Lam Dong) (FIPI 1996).

Remarkable Specimens

A tree-ring chronology from Vietnam’s Bidoup Nui Ba National Park (Buckley et al. 2010) spans 979 years, and is presumably based on living tree material. This chronology was used in a study of long-term precipitation variability.

Ethnobotany

The timber is light, fine and aromatic with straight grain. It was formerly used for coffins. Laotians and Dao tribesmen split the timber for roofing and wall partitioning. It is also used for furniture, art articles, and to produce charcoal of high heat value. Distillation, especially of the root wood, gives an essential oil used for cosmetics and preparation of medicines (FIPI 1996).

Observations

Although it is widely distributed, I am only certain that it can be readily found in the Pu Mat, Vu Quang and Bi Doup Nature Reserves in Vietnam.

Remarks

The discoverer (in 1908) was a Captain A. E. W. Hodgins, whence the specific epithet.

Citations

Buckley, Brendan M., Kevin J. Anchukaitis, Daniel Penny, Roland Fletcher, Edward R. Cook, Masaki Sano, Le Canh Nam, Aroonrut Wichienkeeo, Ton That Minh, and Truong Mai Hong. 2010. Climate as a contributing factor in the demise of Angkor, Cambodia. Proceedings of the National Academy of Sciences 107 (15): 6748–52. https://doi.org/10.1073/pnas.0910827107.

Rushforth, Keith. 2007. Notes on the Cupressaceae in Vietnam. Tap Chí Sinh Hoc 29(3):32-39.

[WCMC] World Conservation Monitoring Centre. The Socialist Republic of Viet Nam Appendix 5 - Threatened Plant Species. http://www.wcmc.org.uk/infoserv/countryp/vietnam/app5.html, accessed 2001.11.25, now defunct.

See also

The species account at Threatened Conifers of the World (where it is listed as Fokiena hodginsii).

Farjon (2005) provides a detailed account (for Fokienia), with illustrations.

Hiep et al. 2004 (as Fokienia).

Luu and Thomas 2004 provides a recent description (of Fokienia), range map, conservation status, drawings and photos, and a wealth of additional information.