Nikko National Park: The Nasu-Kashi Area
The Nasu-Kashi area of Nikko National Park is centered on the Nasu mountain range and straddles the border of Tochigi and Fukushima Prefectures. Winter here is colder than it is in Tokyo, with average January temperatures several degrees below freezing and snow accumulation averaging 20 to 30 centimeters in a typical year. Summer temperatures are also relatively cool, averaging in the low twenties (Celsius).
The Nasu mountain range is a volcanic group centered on the Five Peaks of Nasu (sometimes collectively called Mt. Nasu): Mt. Chausu (1,915 m), Mt. Asahi (1,896 m), Mt. Sanbonyari (1,917 m), Mt. Minamigatsu (1,776 m), and Mt. Kuro-oya (1,589 m). The peaks were formed by volcanic activity that began around 500,000 years ago. Mt. Chausu, the range’s only remaining active volcano, erupted violently from 1408 to 1410, killing more than 180 people and creating the dome of hardened andesite that forms its current summit. Mt. Chausu’s last eruption was in 1881, but numerous hot springs around the mountain indicate ongoing volcanic activity. Fumaroles (volcanic vents) near the peak and base of Mt. Chausu constantly emit sulfurous gas.
The unique environment of the Nasu mountain range gives rise to a highly diverse ecosystem. Firstly, local wildlife has had to adjust to the volcanic conditions over the centuries. Secondly, the area is the boundary of the Pacific Ocean and Sea of Japan ecological zones. Thirdly, the broad highland area south of Mt. Chausu, called Nasukōgen, is home to many high-altitude species, many of which are classified as Vulnerable (VU) or Near Threatened (NT) on the Ministry of Environment’s lists of endangered species.
The Nasukogen Visitor Center provides information on the Nasu-Kashi area and features exhibits on its history, nature, and outdoor activities. The staff can also advise visitors on the area’s many hiking trails.