Surveys supported by the Global Trees Campaign have discovered populations of four threatened trees in new areas of south-west China and northern Vietnam, marking important range expansions or population increases for each species. In China the Endangered Ziyuan fir Abies ziyuanensis is known from just three areas in Jiangxi, Hunan and Guangxi Provinces and is thought to number <600 individuals. With only 50 individuals known to remain in Yinzhulaoshan Provincial Nature Reserve in North Guangxi, field surveys were carried out throughout the 5000 ha Reserve as part of a Global Trees Campaign project (co-funded by Save Our Species) to improve management of the species. Twenty-one A. ziyuanensis individuals, including small seedlings and adult trees, were discovered in three separate areas, increasing the tree's known population in the Reserve from 50 to 71. The discovery of seedlings is particularly significant as it was not known whether natural regeneration was occurring.
In another nature reserve in China surveys have identified new individuals of a species once thought to be confined to Vietnam. The Vietnamese golden cypress Xanthocyparis vietnamensis was first discovered by scientists working in Bat Dai Son Nature Reserve, Quan Ba District, Vietnam, in 1999 and it was not until 2013 that one individual tree was discovered in a limestone area of Mulun National Natural Reserve, northern Guangxi, China. The 2013 discovery was the first record for this species and genus of Cupressaceae in China (Meng et al., 2013, Guihaia, 33, 388–391).
Surveys conducted in 2014 in the 10,829 ha Mulun National Natural Reserve, supported by a small grant from the Global Trees Campaign, found 17 new individuals on two separate limestone mountains at altitudes of 730–826 m, at least 6 km from the tree found in 2013. The population consisted of 15 adult trees (diameter at breast height, DBH, 2.7–25.8 cm) and two seedlings (c. 25 cm tall), confirming the population is capable of natural regeneration. This increased the tree's known population in China from one to 18 individuals. Surveys of the adjacent Maolan National Natural Reserve in Guizhou province, however, which has similar habitats, were unsuccessful.
Across the border in northern Vietnam, 15 mature X. vietnamensis trees (mean DBH 70 cm) were discovered on the border between Ha Giang and Tuyen Quang Provinces, c. 70 km south-west of the original population. These trees were found in similar habitat to the newly discovered population in China, on a limestone outcrop at 1,200 m.
Elsewhere in North Vietnam, as part of a Global Trees Campaign programme to support nature reserves and communities in protecting threatened trees, the Centre for Plant Conservation has made exciting discoveries of highly threatened magnolia species. Once thought to be confined to south-west China, <20 of the Critically Endangered Magnolia grandis were discovered in Ha Giang Province, Vietnam, in 2011. In 2014 a further 15 M. grandis (mean DBH 40 cm) were found in the same area, on a ridge of limestone forest at 1,183 m. At the same time as this discovery, five Magnolia coriacea saplings were discovered at the same location. This indicates a range expansion for this Endangered species, which has a scattered distribution across south-west China and northern Vietnam.
These recent findings of new, discrete populations of threatened trees in southern China and northern Vietnam are promising news for conservationists and for the four species involved. For all four species the Global Trees Campaign is working with local communities and nature reserves to improve management and protection of the wild populations in China and Vietnam.
