Central Chinese Mixed Mesophytic Forest

With their high species diversity and large numbers of canopy tree species these rich temperate forests resemble tropical rain forest. The canopy comprises some 65 genera spread amongst a diversity of unrelated families. They also have a complex vertical structure with up five strata including a crown or canopy layer, a lower tree layer, a tall and small shrub layer, and a herbaceous ground layer. The broad-leaved trees include both deciduous and evergreen species, and each group includes many endemic species. Among the deciduous species are Acer amplum, A. davidii, A. flabellatum, A.  franchettii, A. fulvescens, A. grosseri, A. henryi, A. maximowiczii, A. oliverianum, A. robustum, A. sinense, A. wilsonii, Aesculus wilsonii, Carpinus fargesii, C. oblongifolia, Celtis biondii, C. julianae, C. labilis, Diospyros armata, Evodia hupehensis, Gleditschia macracantha, G. sinensis, Juglans cathayensis, Maackia chinensis, Magnolia cyclindrica, M. sprengeri, M. zenii, Phellodendron chinense, Pterocarya hupehensis, P. paliurus, Salix heterochroma, Tilia henryana, T. oliveri, T. tuan and Zelkova schneideriana.  Evergreen species are less common but still comprise some 15 genera including endemic species such as Eriobotrya japonica (Rosaceae), Illicium henryi (Illiciaceae), Photinia amphidoxa and P. parvifolia (Rosaceae). The floristic composition of the under story of small trees and shrubs is even richer and more varied and, in fact, is unsurpassed by any other deciduous forest. Included here are again many endemic species including Callicarpa bodinieri (Lamiaceae), Cercis chinensis, C. racemosa, (Fabaceae), Clethra monostachya (Clethraceae), Fortunearia sinensis (Hamamelidaceae), Hydrangea sargentiana, H. strigosa (Hydrangeaceae), Ilex cornuta I. szechwanensis (Aquifoliaceae), Jasminum giraldii (Oleaceae), Meliosma beaniana, M. flexuosa, M. veitchiorum (Sabiaceae), Rhamnella franguloides (Rhamnaceae), Stachyurus szechuanensis (Stachyuraceae), Stewartia sinensis (Theaceae), Styrax dasyantha and S. veitchiorum (Styracaceae).  Also unlike most temperate forests there are many woody climbers, and again including many endemic species such as Actinidia melanandra (Actinidiaceae), Clematis apiifolia (Ranunculaceae), Holboellia fargesii (Lardizabalaceae), Kadsura longipedunculata (Schisandraceae), Parthenocissus henryana, P. laetovirens (family), Schisandra sphenanthera (Schisandraceae), Sinofranchetia chinensis (Lardizabalaceae) and Vitis wilsonae (Vitaceae). The ground cover includes many shade tolerant flowering plants and ferns many of which are confined to these shady woodlands. These comprise at least 22 genera including endemic species of Arisaema, Corydalis, Lilium and Smilax.

Also integral to these forests is a rich, indigenous conifer assemblage including at least 15 genera with endemic species such as Ginkgo biloba (Ginkgoaceae), Metasequoia glyptostroboides (dawn redwood) (Cupressaceae), Nothotaxus chienii (Taxaceae), Pseudolarix amabilis (Pinaceae), Pseudotsuga gavsenii, P. forestii, P. sinensis (Pinaceae) and Torreya grandis (Cephalotaxaceae).  Ginkgo biloba occurs in the foothills of western Tienmu-Shan often in association with Pseudolarix amabilis, while Metasequoia glyptostroboides is restricted to the forests at the Szechuan-Hopeh border often in association with the conifer Taiwania cryptomeroides, which was once thought to be endemic to Taiwan. Both Ginkgo and Metasequoia were only known from the fossil record prior to being discovered in China, and in fact, the Ginkgo is one of the oldest known gymnosperms dating back to the early Mesozoic.  The Metasequoia was first described from the lower Pliocene, and both this species and Taiwania are members of the Taxodiaceae and closely related to the giant redwoods of North America. In the mild climate of the early to mid Tertiary Period, the fossil record tells us that Metasequoia, like the North American red woods, formed extensive northern forests, and in fact, its unusual deciduous habitat for a conifer is thought to be an adaptation to the Arctic night. Other endemic species associated with Metasequoia, and possible relics of the Tertiary forests, include Abelia uniflora (Caprifoliaceae), Celastrus hypoleuca (Celastraceae), Corylopsis platypetala (Hamamelidaceae), Emmenopterys henryi (Rubiaceae), Eucommia ulmoides (Eucommiaceae), Gymnocladus chinensis (Fabaceae), Liriodendron chinense (Magnoliaceae), Nyssa sinensis (Cornaceae), Poliothyris sinensis (Flacourtiaceae), Polygala wattersii (Polygalaceae), Rhamnus utilis (Rhamnaceae), Sassafras tzumu (Lauraceae), Tapiscia sinensis (Tapisciaceae), Tetracentron sinense (Trochodendraceae), Trollius yunnanensis (Ranunculaceae), and Zelkova schneideriana (Ulmaceae).

The dawn redwood forests occur in Shuisha-Pa (Metasequoia Valley)in the remote areas of the upper Yangtze. Compared with the lower Yangtze, the forests here also support many other endemic species. For example in the forests of Szechan the endemic or near endemic genera Bretschneiddera (B. sinensis), Davidia (D. involucrata), and Rhoitpelea (R. chiliantha) occur, while other endemic or near endemic taxa typically found in the upper Yangtze forests include Dipteronia sinensis (Sapindaceae), Euptelea pleiosperma (Eupteleaceae), Fagus engleriana (Fagaceae), Fokienia hidginsii (Cupressaceae), Sinowilsonia henryi (Hamamelidaceae) and Staphylea holocarpa (Staphyleaceae). 

Further information required.

 

References

Chia-Chi, H. & Tsen-Li, C. 1993. Halophytes in China: Floristic distribution and vegetation types. In: Towards the rational use of high salinity tolerant plants. Eds. H. Lieth & A. Al. Masoom. Kluwer Academic Publishers.

Hu, S. Y. 1980. The Metasequoia flora and its phytogeographical significance. Journal of the Arnold Arboretum, 60: 41-94.

Hou, H. Y. 1983. Vegetation of China with references to its geographical distribution. Annals of the Missouri Botanical Garden, 70: 509-549.

Ji, Z., Guangmei, Z., Huadong, W. & Jialin, X. 1990. The Natural History of China. Collins.

López-Pujol, J., Zhang, F-M., Ge, S. 2006. Plant biodiversity in China: richly varied, endangered, and in need of conservation. Biodiversity and Conservation, 15: 3983-4026.

Richardson, S. D. 1977. Forestry in communist China. The John Hopkins Press.

Songqiao, Z. & Huaxun, L. 1989. Shrublands of China. In: The Biology and Utilization of Shrubs. Ed. C. M. McKell. Academic Press, Inc.

Taylor, A. H. & Zisheng, Q. 1988. Regeneration patterns in old-growth Abies-Betula forest in the Wolong natural reserve, Sichuan, China. Journal of Ecology, 76: 1204-1218.

Wang, Chi-Wu. 1961. The forests of China with a survey of grassland and desert vegetation. Maria Moors Cabot Foundation. Publication No. 5.

Xie, Z. 2003. Characteristics and conservation priorities of threatened plants in the Yangtze valley. Biodiversity and Conservation, 12: 65-72.

Zhang, Yin-Bo & Ma Ke-Ping. 2008. Geographic distribution pattern and status assessment of threatened plants in China. Biodiversity and Conservation, 17: 1738-1798.