With conspicuous similarity in ecological and floristic characters to the forests of southeast Asia, the forests in southern China (from southeastern Tibet and southern Yunnan to southwestern Guangxi, southern Taiwan and Hainan, mainly south of 22°30'N latitude ) are considered to be a northern extension of those Asian forests.  

By consulting a large amount of literature, Prof. ZHU Hua of Xishuangbanna Tropical Botanical Garden (XTBG) of the Chinese Academy of Sciences reviewed studies of the tropical forest in China in order to define its characteristics and circumscription.

He discussed the northern boundary of the frost-free areas in China and highlighted current threats to biodiversity in the forests. 

In his review, the forests of southern China share similar physiognomic characteristics, but vary in floristic composition and species diversity. As the forest nears its climatic limits, a change in physiognomy occurs between seasons. Chinese botanists have used the term ‘tropical seasonal rain forest’ for this type of forest. 

 Southern tropical forests with the most species have lost tree diversity after rubber and Eucalyptus plantations replaced them. The major change in land use in southern China has been an increase in rubber and Eucalyptus plantations and a decrease in natural forests. The direct results are biodiversity loss and forest fragmentation. 

Three main factors resulting in the loss of biodiversity of the tropical forest in southern China have been recognized: 1. rubber and pulp plantations replacing the forests; 2. fragmentation of the forests and 3. economic plant cultivation in the forest understory.  

The expansion of rubber (in Yunnan and Hainan) and Eucalyptus (in Hainan) monocultures have been the principal factors leading to loss of biodiversity. The high price of rubber encourages expansion of rubber plantations.  

The botanist suggested that we need limit further expansion of rubber and Eucalyptus plantations and promote multispecies agroforestry systems in the southern tropical forests of China. 

The study entitled “The Tropical Forests of Southern China and Conservation of Biodiversity” has been published online in Botanical Review.