Stand Structure and Geographic Conditions of Natural Selection Forests in Central Hokkaido, Northern Japan(<Special Issue>Multipurpose Forest Management)

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Selection forest is a forest managed with the uneven-aged silvicultural system, in which trees are removed individually from a large area periodically. Selection system has been used to manage natural forests in Hokkaido, northern Japan. This study demonstrated the characteristics of natural selection forests in central Hokkaido. A case analysis was conducted at the University of Tokyo (UT) Hokkaido Forest to closely examine the structure and geography of selection stands. We used a total of 1,382 sample plots that had established in selection stands during 1996-2005 and the spatial information on stand classification with 10-m grid digital elevation model. We calculated the mean dominance and density of trees with DBH≥5 cm, which were 30.7 m^2 ha^<-1> and 792 individuals ha^<-1>, respectively. Juveniles (Height≥1.3 m and DBH<5 cm) had a mean density of 561 individuals ha^<-1>. An asymmetric and peaked distribution was observed in tree and juvenile density. The predominant tree species included Sakhalin fir (Abies sachalinensis), Yezo spruce (Picea jezoensis), Japanese linden (Tilia japonica), and painted maple (Acer mono). An inverse J-shaped diameter distribution was maintained in tree density. Selection stands were mostly located on an area between 300-600 m a.s.l..