A vertical look at climate zones
The Changbai Mountain Biosphere Reserve demonstrates a complete and clearly defined vertical zonation of vegetation. This stratification is driven by a steep drop in temperature with increasing elevation. The mountain's base, below 1,100 meters, is a mixed forest of coniferous and broad-leaved trees. Dominant species here include the Korean pine (Pinus koraiensis), Mongolian oak (Quercus mongolica), and Manchurian lime (Tilia mandshurica).
From 1,100 to 1,900 meters, the landscape transitions into a "dark conifer" belt. This zone is composed primarily of cold-tolerant evergreens like Khingan fir (Abies nephrolepis) and Yezo spruce (Picea jezoensis). Above this, from roughly 1,800 to 2,100 meters, hardy Erman's birch (Betula ermanii) forms the upper forest boundary. The summit, above 2,100 meters, is an alpine tundra zone. Here, the ground is covered by snow for up to nine months of the year, and only low-lying shrubs like rhododendrons and alpine meadows can survive the harsh conditions. This entire ecological succession from temperate forest to arctic-like tundra occurs over a horizontal distance of just 50 kilometers.
The volcano and its Heaven Lake
The reserve is centered on an active stratovolcano, known as Changbai Mountain in China and Paektu Mountain in North Korea. At its summit, at an elevation of 2,189 meters, lies Tianchi, or "Heaven Lake". This body of water fills a massive caldera formed by past eruptions. The lake covers an area of 9.8 square kilometers and has a maximum depth of 373 meters, making it the deepest lake in China.
The caldera was shaped in large part by the "Millennium Eruption" of 946 CE. This event was one of the largest explosive eruptions in the last 10,000 years, with a Volcanic Explosivity Index (VEI) of 6 or 7. It ejected an estimated 23 cubic kilometers of material and deposited ash as far away as northern Japan. While the volcano is currently dormant, geophysical evidence indicates the presence of magma chambers beneath the surface, confirming its active status. The lake itself is fed by precipitation and snowmelt, and its water is perpetually cold, rarely exceeding 15°C in the summer and freezing over completely in winter.
A protected biodiversity hotspot
The Changbai Mountain area was established as a nature reserve in 1960 and was one of China's first reserves to join UNESCO's Man and the Biosphere Programme in 1979. The reserve covers an area of 1,965 square kilometers and is a critical habitat for a vast number of species. It hosts over 1,586 species of wild animals and 2,639 species of wild plants.
The diverse forests provide habitats for numerous rare and endangered animals. These include large predators like the Siberian tiger (Panthera tigris altaica) and the Amur leopard (Panthera pardus orientalis), which have been recorded returning to the region. Other notable species include the Asiatic black bear (Ursus thibetanus), sable (Martes zibellina), and the endangered scaly-sided merganser (Mergus squamatus), a rare duck with fewer than 5,000 individuals left in the wild. The reserve's intact ecosystems serve as an important "gene bank" for species and a site for long-term ecological research.