Location and General Description
The Central Korean Deciduous Forests ecoregion occupies most of the Korean Peninsula except for the southern coastal margin and the mountainous north. Korea is a mountainous peninsula extending south-southeast from the northeastern part of the China mainland. The mountains are not high, rarely exceeding 1,200 meters, but they are found almost everywhere and, consequently, the terrain may be said to be rugged and steep. Receiving abundant summer precipitation with warm, humid weather, the Korean Peninsula is part of the East Asian monsoonal region. Annual precipitation exceeds 1,000 mm throughout most of the peninsula, with about two-thirds falling between June and September. During winter, movement of air from the Asian continent brings cold temperatures and generally dry conditions, although some snowfall occurs. Spring and autumn are mild and of short duration. Mean temperatures in the western coastal lowlands are 22.5° to 25°C in July and -5° to - 2.5°C in January. Precipitation totals tend to vary considerably from year to year and droughts are not infrequent. Although the Korean Peninsula receives some typhoons, it is less vulnerable than other parts of East Asia, such as Japan, Taiwan, and the east coast of China.
Typical vegetation of the temperate middle regions of this large peninsula includes a deciduous hardwood forest that varies floristically from south to north. As in the hardwood forests of northeastern North America, conifers occur in places that are especially cold or recently disturbed. The warm-temperate southern part of the ecozone includes the hornbeam species Carpinus tschonoskii and C. laxiflora. Other characteristic species in the southern part are pine Pinus thunbergii, maple Acer formosum, A. palmatum, oak Quercus acutissima, and snowbell Styrax. The bamboo Phyllostachys is also characteristic of this warm temperate area, although it occurs mainly in areas that have been disturbed by forest clearing or cultivation. The cool-temperate northern part supports forests of the oak species Quercus mongolica, Q. serrata, and the fir Abies holophylla. Other cool temperate deciduous trees include Acer mono, birch Betula, Carpinus, Celtis chinensis, Korean ash Fraxinus rhynchophylla, walnut Juglans mandshurica, Maackia amurensis, Platycarya strobilacea, Prunus padus, Pyrus ussuriensis, willow Salix, and elm Ulmus.
The fauna of the lowland regions of the Korean Peninsula is closely related to that of southern Manchuria, central China, and Japan.
The critically endangered crested shelduck Tadorna cristata, once occurred along the Korean Coast. Two endangered crane species occur on the Korean Peninsula. Extremely rare Red-crowned cranes (Grus japonensis) overwinter along rivers and in coastal and freshwater marshes and breed in deep freshwater marshes. White-naped cranes (Grus vipio) winter here. Both of these species (more than 600 individuals) now breed in the demilitarized zone (DMZ) that separates North Korea and South Korea. The DMZ is a critical stopping-off point during the annual migration of these birds from breeding grounds in northeastern China and southeastern Russia. The white-bellied black woodpecker (Dryocopus javensis richardsi) is native to Korea and has been designated as "Natural Monument No. 197." Because this subspecies prefers to nest in holes in old trees located in dense forests, it has become extremely rare as its late-successional forest habitat has dwindled. Birds include fairy pitta (Pitta nympha), and ring-necked pheasant (Phasianus colchicus torquatus). South Korea, including this ecoregion and the Southern Korea Evergreen Forests ecoregion, records 379 bird species of which 114 species breed. The others are either vagrants, migrants or winter visitors.
Mammals include black bears, deer, mandarin voles and other Palaearctic species. Large predatory mammals such as wolves have been severely reduced by millennia of hunting and intensive agriculture. Smaller predators like badgers, marten and weasels still occur in the more remote forested areas of the hills.
The middle and southern mountain regions support several endemic tree species including the conifers Thuja koraiensis and Abies koreana. Korean ginseng Panax ginseng was once common in the understory of conifer forests throughout the northern part of the Korean Peninsula and Manchuria, and perhaps in the hilly parts of this ecoregion as well. In recent decades, this plant has been greatly reduced due to timber harvesting, wildfire, and collection of the root for medicinal purposes. Today P. ginseng is probably extinct in both Chinese Manchuria and on the Korean Peninsula, although it still occurs in the understory of forests in the Primorsky Krai area of the Russian Far East.
As in many parts of East Asia, low-lying plains have been converted to agriculture land. Thus the remaining Central Korean Deciduous Forest is mostly confined to the mountains and hills that cover an extensive area of the Korean Peninsula. The southwestern part of the ecoregion supports very little of its potential vegetation.
Types and Severity of Threats
Certain measures that weaken the productivity and health of forest ecosystems include the expansion of monocultures, frequent occurrence of damages by fire and pests, increase of air pollution, and conversion of forests for other purposes.
Justification of Ecoregion Delineation
This ecoregion consists of Yim's (1968; also Yim 1977) southern and middle sections of deciduous broadleaf forests (zones B1 and B2) in the warm-temperate climate zone. Major species include Acer formosum, Carpinus laxiflora, C. tschonoskii, Quercus mongolica and Q. serrata (Ching 1991).
Ching, K.K. 1991. Temperate deciduous forests in East Asia. Pages 539-555 in E.Röhrig and B. Ulrich, editors. Ecosystems of the world 7: temperate deciduous forests. Elsevier Science Publishers B.V., Amsterdam, The Netherlands.
Kong, Woo-Seok and David Watts. 1993. The Plant Geography of Korea with an Emphasis on the Alpine Zones. Kluwer Academic Publishers. Dordrecht, The Netherlands.
Yim, K.B. 1968. Jorimhak Wonron (Principles of Silviculture). Hyangmunsa, Seoul. (in Korean)
Yim, Y.J. 1977. Distribution of forest vegetation and climate in the Korean peninsula: IV zonal distribution of forest vegetation in relation to thermal climate. Japanese Journal of Ecology 27: 269-278.
Prepared by: Chris Carpenter
Reviewed by: In process