The essential characteristics and main types of the broad-leaved evergreen forest in China
The broad-leaved evergreen forest (BLEF) is one of the most important vegetation types in the subtropical region of China. It is distributed between 24° and 32° N, 99° and 123° E. Its northern boundary runs from the southern foothills of Michang and Daba Mountains, along the southern bank of Yangtse River to Hangzhou Gulf; and the southern boundary runs from the northern part of Hongshui River along the south slope of Nanling Mountains to the Minjang Estuary. In the west it borders at the crest of the mountains lying in the western parts of the provinces Sichuan and Yunnan. In the east it reaches the southeast coast of East China Sea and the islands near the coast. South of this region, BLEFs appear in the mountain belt. This vegetation type was given different names, for example "temperate rain forest" (Schimper 1903), "warm temperate rain forest" (Polunin 1960), "moist temperate subtropical forest" (Alechin 1950), "Laurisilvae" or "Lorbeerwald" (Rübel 1930), etc. In China, however, it is commonly named subtropical broad-leaved evergreen forest and has been recognized as zonal vegetation type or climatic climax of the central part of subtropical zone (Wu 1980). This kind of forest is not only different from the mediterranean sclerophyllous forest, but also from the broad-leaved evergreen forests in certain parts of the southern hemisphere (Chile, New Zealand, Tasmania etc.), as well as from the broad-leaved evergreen forests in the southeastern part of USA. It is a special geographical isolation type which developed under the monsoon climatical conditions of Eastern Asia. From the centre and south of China this vegetation type extends into the centre and south of Japan, and to the south of Korea. Due to differences in the concepts of the climatic zones, it is called warm temperate broad-leaved evergreen forest in Japan (Suzuki 1963; Numata 1974; Kira 1978; Miyawaki 1976, 1979). The BLEF was very common in China; it was widely distributed over the land. But later owing to the land reclamation for cultivation and the economic exploitation of the forest, the primeval BLEF areas become smaller and smaller. Most of them are replaced by secondary forest and thicket, except for remote mountain regions. Where they are inaccessible for transportation, still exist certain reserves of BLEF. It is little known among botanists outside of China; therefore I am going to describe some essential characteristics and main types of BLEF in this paper.