The low hills and mountains at the base of the Korean Peninsula support some of the most diverse forest ecosystems in northeast Asia. Vertical zonation is rather pronounced here, which accounts for the higher biodiversity. The Changbai Mountains consist of low to middle elevation hills aligned southwest to northeast and include a volcanic plateau situated at an elevation over 2,600 m. This upland is the source of several major rivers of the region ( Songhua, Tumen, Yalu,etc) and supports a distinctive alpine flora. Baiyun (White Cloud), the highest peak in northeast China, is a dormant volcano that reaches an elevation of 2,691 m. Because of its great range in elevation, this ecoregion includes well-defined bioclimatic zones from temperate vegetation in the valleys to alpine tundra on the upper slopes. Due to the isolation of these high-elevation habitats, the region also supports numerous endemic plant species.
Forests in the Changbai Mountains are the richest in northeast China. Low-elevation areas below 1,100 m support mixed stands of conifers and deciduous broadleaf trees. Conifers include Korean pine (Pinus koraiensis), fir (Abies holophylla), red pine (Pinus densiflora), and Japanese yew (Taxus cuspidata ssp. Latifolia). Deciduous broadleaf trees include Mongolian oak (Quercus mongolica), Tilia amurensis, ash (Fraxinus mandschurica), and dwarf birch (Betula ermanii). Plant species with a subtropical affinity also occur in these forests. Examples include woody climbers such as native Chinese gooseberry(Actinidia spp.), or kiwi fruit, and "Dutchman’s pipe" (Aristolochia mandshuriensis). These lower elevation forests are similar and transitional to the surrounding Manchurian Mixed Forests ecoregion. Understory vegetation includes economically important, and in some cases much depleted, species such as ginseng (Panax ginseng), Manchurian wild ginger (Asarum heterotropoides), and Gastrodia spp. which is used as an analgesic.
The "dark conifer" forest zone at 1,100 to 1,900 m includes a species-rich assemblage of plants that trace their origins to Siberia, western Eurasia, Japan, and the Korean Peninsula. The forest here is cloaked in moss and supports an understory of forbs, grasses, and ferns. At 1,100 to 1,500 m, the forest consists of spruce (Picea jezoensis, P. obovata), fir (Abies nephrolepis), and larch (Larix olgensis). At 1,500 to 1,900 m, the tree diversity declines to stands composed of Picea jezoensis and Abies nephrolepis with a reduced understory and dense moss layer. Sub-canopy vegetation in the dark conifer forest includes maple (Acer ukurunduense), birch (Betula castata),mountain ash (Sorbus pohuashanensis), and poplar (Populus ussuriensis).
Alpine elevations support a variety of forb species. Exposed sites support meadow, but in favorable locations where snow protects exposed buds during winter, woody shrubs such as willow (Salix spp.), Vaccinium spp., Rhododendron spp., and dwarf rock birch (Betula ermannii)form a low groundcover. Panax ginseng is nearly extinct throughout Chinese Manchuria on the Korean Peninsula, but it still occurs in Changbaishan National Nature Reserve. Alpine plants of the summit plateau on Mount Baiyun are distinctive and include many endemic species because the Changbai Mountains are the only alpine peaks in this region of Asia.
More than 50 mammal species and 300 bird species have been recorded on Changbaishan. Mammals include Fareast leopard (Panthera pardus orientalis), lynx (Lynx lynx), brown bear (Ursus arctos), Sika deer (Cervus nippon), red deer (C. elaphus), goral (Nemorhaedus goral), wild boar (Sus scrofa), otter (Lutra lutra), and sable (Martes zibellina).Birds include rare species such as black stork (Ciconia nigra), Mandarin duck (Aix galericulata), and scaly-sided merganser (Mergus squamatus).
The internationally famous Changbaishan NNR is a Man and the Biosphere Reserve and the most prominent protected area in the ecoregion and the site of many research projects. On the North Korean side it borders Paekdusan National Park. On the northeastern border of this ecoregion there is a vital link in tiger and leopard habitat formed by Hunchun NNR in China and three border nature reserves in southern Primorsky Province in Russia (Kedrovaya Pad, Barsovy, and Borisovskoye Plateau).