Mount Daisen – A holy mountain

Mount Daisen (1729m) is the largest mountain in the Chugoku Mountain range in western Japan.
Mount Daisen is mentioned in ancient Japanese texts such as the Izumo-no-kuni Fudoki, written in 733. In these ancient texts Daisen is described as the very centre point of Japan and even as a God itself. The name “Daisen” translates directly as “Great Mountain”, and is a shortened version of the name “Great God Mountain” as it was previously known.

Due to the belief that it was a sacred area, much of the upper areas of Mount Daisen were strictly off-limits to common people until the end of the Edo Period (1868). As a result, the extensive beech tree forests around the peak were spared much of the deforestation that occurred across most parts of Japan. These beech forests remain to this day and their root systems act as an important water filter to the slopes and agricultural areas below. This has resulted in very mineral-rich and fertile conditions around the mountain which are important for human activity and wildlife alike.

The Nawa River Basin – A very special Japanese giant salamander habitat in a very special place

The Nawa River Basin is located on the northern slopes of Mount Daisen and flows into the Sea of Japan in Daisen Town. It consists of three main branches: the Nawa River, the Otani River and the Higashi-dani River. The rivers are short and steep and are fed a constant supply of cool water from the mountain. The total length of the main Nawa River is just 4.10kms from source to ocean.

The average annual rainfall in Daisen Town is 1948mm. As a point of comparison, London in the UK receives 583.6mm per year. A lot of the water that filters through the beech forests and rocky slopes of the mountain is snowmelt. This is an important factor for the Japanese giant salamanders as the mountain’s rivers remain cool until very close to the ocean. Cooler water is richer in oxygen than warmer water. The Japanese giant salamander, which absorbs oxygen through their skin, requires fast flowing oxygen-rich water in order to thrive and survive. It is this fact that enables Japanese giant salamanders to exist in relatively high numbers at such low altitudes in the Nawa River Basin.

Unfortunately, despite the hard work of some local nature conservation groups and individuals, many aspects of Daisen’s natural beautiful resources and wildlife are being neglected, mismanaged, or even destroyed. Unless these patterns of environmental harm are reversed, the Japanese giant salamander will no longer be able to live in the Nawa River Basin.