Changbai Mountain Underground Forest (Dixia Senlin)

The Underground Forest, or Dixia Senlin, is a sunken forest valley on the North Slope of Changbai Mountain in Antu County, Yanbian Korean Autonomous Prefecture, Jilin Province. The valley lies about 100 m below the surrounding plateau and was formed by volcanic collapse and later river erosion, which gave it the name of a forest below ground level. Spruce, fir and larch grow densely on the valley floor and slopes, so the area feels cooler and darker than the plateau above. Access is by the North Slope eco-bus loop, which has a stop at the Underground Forest, or by taxi from Erdaobaihe Town. Entry is included in the North Slope ticket and eco-bus fare, about USD 28 combined. A boardwalk descends into the valley and returns by the same route or a short loop, with a total length of about 2-3 km and about 100 m of descent and re-ascent. The walk takes 1-1.5 hours and is rated easy, although the return climb on steps can tire visitors who rush the descent. The surface is wooden boardwalk and stairs with handrails, and shade is nearly continuous under the canopy. Landmarks include the viewing platform at the rim looking over the treetops, the quiet valley floor with moss-covered logs, and interpretive signs on the forest ecosystem. The turn-around point is flexible, since several platforms along the descent allow visitors to return early. Water is not reliably available on the trail, so a bottle should be carried from the car park. There are no huts on the boardwalk, although the covered rest areas near the entrance offer some shelter. Insects are common in summer, so repellent is useful, and autumn brings colour in late September. The stop pairs well with the Grand Canyon and Waterfall visits on the same loop.