Daisen-Oki National Park: Terrain and Ecology
Perhaps the most distinguishing feature of Daisen-Oki National Park’s four areas is the diverse terrain and ecology found within them. The mountainous regions surrounding Mt. Daisen (1,729 m), Mt. Hiruzen (1,202 m), and Mt. Sanbe (1,126 m) were shaped by volcanic activity, and several of each mountain’s peaks are hardened lava domes formed by multiple eruptions. Their sides are blanketed with pristine beech forests that shelter rare, high-altitude plants. On the Hiruzen Highlands and around the bases of Mt. Sanbe and Mt. Senjō (615 m), broad swathes of grassland are maintained by annual controlled burning, an age-old tradition that preserves the grassland habitats of resident endangered species. Lakes, too, are a part of the mountain topography, formed as rainwater and snowmelt collected in depressions within the volcanic craters.
Moving toward Shimane Peninsula and the coastal region, a shoreline of volcanic rock has been intricately carved and hollowed out by winter winds and the rough waves of the Sea of Japan. Sea caves, grottos, and islets weathered into fantastic shapes dot the coast beneath these rugged cliffs.
The Oki Islands are a virtual time capsule for geological and ecological studies. Formed by two volcanoes between 6 million and 5.5 million years ago, the islands were periodically connected to the Japanese mainland as the sea levels rose and fell. During those periods, plants and animals migrated in both directions. Today, the Oki Islands preserve many unique species and subspecies that cannot be found anywhere else in the world. The islands were designated a UNESCO Global Geopark in 2015 for their geohistory, unique ecosystem, and distinctive local culture.