The tree-skiing in Japan is unmatched, due to the almost perfect spacing of the birch and beech, creating a natural slalom course. However, the practice comes with risks. The largest is tree wells, or loose snow around the base of a tree that can trap a fallen skier. Also, while the coastal snowpack in Japan is more stable than other regions, avalanches can still happen. The most common type are glide cracks, which start small but can lead to larger slides, especially in steeper glades and shoots.
AloJapan.com