Vegetation of Yunnan and Hainan Provinces, China Hajinle MAKITA

Geographical Review of Japan Vol. 62 (Ser. B), No. 2, 116-126, 1990 Vegetation of Yunnan and Hainan Provinces, China Hajinle MAKITA* and Hiroyoshi CHUJO** Abstract From the viewpoint of floristic geography, Yunnan and Hainan like other areas in South China are transitional areas between Holarctic and Palaeotropic Floral Kingdoms. Accordingly, plants of both floral kingdoms are mixed together. Besides, there are many indigenous taxa of plant. Physical conditions, especially in Yunnan, are very complicated; local differences in habitats are great. Thus, various types of plant communities are found from tropical rain forest to arctic vegeta tion in summit areas. Special interest is paid to sclerophyllous oaks and their communities. Key words: South China, vegetation. Fujian Province) of the China-Japanese Forest I. FLORA OF YUNNAN AND Plant Sub-region. HAINAN PROVINCES The palaeotropical area in the south of the boundary is called the Malaysia Plant Sub I-1 Floral regions region, consisting of the Dian-Mian-Dai District Yunnan and Hainan Provinces, along with (mid-reach region of the Nujiang (Salween), the those southern Chinese regions such as Guangxi Mekong and the Yuanjiang in the southwestern Autonomous Region, Guangdong and Taiwan part of Yunnan), the Beibu Bay District (Guang Provinces, constitute transitional areas from the xi Autonomous Region south of the Zhujiang Holarctic to the Palaeotropic Floral Kingdoms. and Guangdong Province), the Nanhai District According to Phytogeography of China, Vol. (Nanhai Islands including Haanan Is.) and the 1(1983), the boundary between both kingdoms Taiwan District (Taiwan Province). runs from the neighborhood of Mt. Gaoli Gong That is, the southern part of Yunnan and the shan near the national border to Myammar in whole of Hainan belong to the Palaeotropic western Yunnan, through Wenshan City in Yun Floral Kingdom and the northern half of Yun nan near the Vietnamese border and through the nan belongs to the Holarctic Floral Kingdom. mouth of the Zhu River in southern Guangdong TAKHTAJAN(1986) draws this kind of bound Provine, reaching the Taiwan Straits (Fig. 1). ary in almost the same area. In his case, however, On the north of this boundary lies the southern north of the boundary, including the greater part marginal area of the Holarctic Floral Kingdom. of Taiwan Province, is the Eastern Asiatic This area is divided into the Hengduan Range Region and south of it is the Indochinese Region District (southeastern half of the Qinghai consisting of the greater part of the Malaysian Tibetan Plateau, western half of Sichuan Peninsula, Indo-Chinese Peninsula and the Province and northwestern part of Yunnan western half of the Nanhai Islands. Province) and Yunnan Plateau District (the I-2 Taxa bounded by the boundary greater part of Yunnan north of the Yuanjiang (Honghe River) of China-Himalaya Forest Plant This boundary of the two floral kingdoms Sub-region, Dian-Qian-Gui District (western half delimits the distribution of holarctic taxa, of Guizhou Province and Guangxi Autonomous Fagaceae, Betulaceae, Juglandaceae, Salicaceae, Region) and Huanan District (Guangdong and etc., and Palaeotropical taxa, Dipterocarpaceae, *College of Liberal Arts , Hirosaki University, Hirosaki, Aomori 036. **College of International Studies , Chubu University, Kasugai, Aichi 487. Vegetation of Yunnan and Hainan Provinces, China 117 Figure 1. Floral regions of southern China Ficus of Moraceae, Simaroubaceae, Euphorbia than 2,000m in elevation. ceae, Sapindaceae, etc. But, as these areas are I-3 Indigenous taxa and the relation with a transitional zone between two floral kingdoms, neighboring areas elements of both kingdoms are found in the same region according to the local habitat conditions, Both the large inland region of Yunnan such as thermal conditions varying with altitude. (380,000km2) and the small island of Hainan The dominant species of mountainous forest (32,200km2) are famous for the abundance of in Hainan, for instance, are holarctic fagaceous their plant species: families, genera and species trees such as Lithocarpus, Castanopsis and Cy are all rich in number in both areas as shown in clobalanopsis. Table 1. It is especially noteworthy that Hainan, In Yunnan, where landforms are more com in spite of its small size, has more than 2,400 spe plicated and relative relief is greater, plants of cies and Yunnan has nearly half of all the plant both kingdoms are mixed in a more complex way. In Xishuangbanna, which belongs to the Table 1 Number and share of plant taxa in Dian-Mian-Dai District of the Palaeotropic Yunnan and Hainan. Floral Kingdom, such summergreen trees as Pru nus, Betula and Quercus are often found on hil ly land of 800-1,000m in elevation, and secondary vegetaions of tops and ridges of hills are composed of those summergreen tree species in many cases. On the contrary, as mentioned below, because of the hot and dry conditions * from Vegetation of Yunnan along large valleys, Bauhinia and other tropical ** from Plant Geography Vol. 1 elements are found even around Dali City, which is located on holarctic Yunnan Plateau of more 118 H. MAKITA, and H. CHUJO species growing in the whole Chinese territory. western (sub-dry) monsoon forest and rainforest At the same time, they are well known for their sub-region of the tropical monsoon forest and indigenous taxa. About 40% of Hainan's spe rainforest region. Hainan belongs to the eastern cies are said to be indigenous. More than 1,000 (sub-humid) monsoon forest and rainforest sub species (1010) are indigenous to Yunnan (Vege region of the last region. The names for these tation of Yunnan, 1987). regions and sub-regions are all taken from Vege From the viewpoint of commonness with tation of China (1980) neighboring areas, among all the species of Hai In the location of boundaries, extent of each nan, 70% are common to the Huanan area, 60% area and nomenclature, Chinese articles show to Vietnam, 58% to the Phillippines and 45% many differences from each other. Even com to Taiwan Province (Physical Geography of Chi paring articles dealing with vegetaion and for na, 1983; MASAMUNE,1975). This is caused by estry, those differences are fairly large. They the fact that Hainan is a continental island which should be made more consistent in the future. was separated from the continent during the Table 2 shows the main examples of vegetation Quaternary. While in Yunnan, as mentioned al land classifications as well as floral land clas above, the boundary of both floral kingdoms sifications of Yunnan and Hainan. runs from west to east, so that the area north II-2 Plant communities of Hainan of it has a high degree of commonness with the Qinghai-Tibetan and Himalayan Plateaus and Hainan Island is mainly covered with the ever the area south of it to India, Myammar and green monsoon forest, montane rainforest and Thailand. The southeastern part of Yunnan, savanna, accompanied with other vegetation however, has a high degree of commonness with types covering smaller areas, namely summit the Indo-Chinese Peninsula, especially with mossy scrub, montane evergreen forest and man Vietnam groves (Ministry of Forestry, Dept. of Survey and Planning, 1981). II PLANT COMMUNITIES OF Evergreen monsoon forest occupies the areas of more than 350m in elevation in the southern, YUNNAN AND HAINAN western, southwestern and northwestern parts of II-1 Vegetational regions the island where the alternation of rain and dry seasons is remarkable. Its upper limit varies lo The above-mentioned aboundary between cally from 950 to 1,200m in elevation. Compo floral kingdoms is almost parallel to a larger sition of tree species is rather simple, consisting vegetational boundary (Fig. 2). The vegetation of evergreen Ebenacea and Lauracea as well as al region to the north of it is the subtropical ever deciduous elements such as. Gossampinus green broadleaved forest region and another to malabarica, Terminaria catappa, Arbizzia spp., the south is the tropical monsoon forest and rain Liquidamber formosana, etc. fairly large in num forest region (Vegetation of China, 1980). ber. Trees are not so large, 10-15m in height The northernmost part of Yunnan, Diging and 15-30cm in DBH. Human destruction of Zangzu Autonomous District, however, belongs this type is very severe. to the southeastern plateau cold-temperate Montane rainforest covers the warm and wet coniferous forest sub-region of the Qinghai southern part of the island to a large extent. Ver Tibetan Plateau cold-alpine vegetation region . tically, the distribution of this type is the same The easternmost part of Yunnan, Zhaotong Dis as the last one. Along with tropical elements such trict, belongs of the eastern (humid) evergreen as Dipterocarpaceae, Sterculiaceae, Sapindaceae broadleaved forest sub-region and the central and Ficus of Morceae, holarctic fagaceous ever part of the norhtern half of Yunnan belongs to green trees dominate the forest. Also conifers the western (semihumid) evergreen broadleaved such as Podocarpus inbricatus, Dacridium pier forest subregion of the subtropical evergreen ri, etc. are found. This type is a forest of large broadleaved forest region. The southern part of size trees of 25-30m in height and 50-80cm Yunnan, on the other hand, belongs to the in DBH. A large number of trees has buttress Vegetation of Yunnan and Hainan Provinces, China 119 Figure 2. Vegetational regions of southern China roots, and cauliflowery and lianas are often and deciduous trees such as Gossampinus found. A canopy is composed of three layers of malabarica, Syzygium spp., Quercus acutissima, which the uppermost one is the emergent layer etc., can hardly be found because of the human with scattering trees. Bamboos and large herba influences. Like similar vegetation in Yunnan, ceous plants compose layers on the forest floor. induced cactus, Opuntia dillenii, is often found In spite of these tropical characters, we can find in a wild state.

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