The Ogasan Nature Reserve has been recently registered as a natural monument.
Covering an area of over 6 500 hectares, it is located in the boundaries between Hwaphyong County, Jagang Province and Kim Hyong Jik County, Ryanggang Province.
The name Ogasan derived from the fact that five peaks with an elevation of 1 000 metres are located in the primeval forest.
As the reserve is located in the boundaries between subarctic zone plant area and temperate zone plant area, it has diversified species composition.
In the area below 700 metres, there grow many Mongolian oak, Acer meno, elm, castor aralia and Amur cork, and few needle-leaf trees such as pine-nut and fir trees.
Distributed in the area between 700 to 1 000 metres are coniferous forests, broadleaved forests and mixed coniferous-broadleaved forests. In the area above 1000 metres there are such coniferous trees as Abies nephrolepis, spruce, pine-nut tree, yew and fir, and such broadleaved trees as white birch and Korean poplar.
Larger numbers of animals inhabit the reserve than other areas.
In the past, the area centred on 800 hectares of a primeval forest had been registered as the Ogasan Primeval Forest, a natural monument.
Besides, individual trees such as a 1 100-year-old yew were designated as natural monuments for conservation.
The reserve is of great significance in academic research and sci-tech dissemination for a long history of its formation and abundance of diversified and unique biological resources.