Regeneration Traits of Four Dominant Species in a Cool-Temperate Conifer-Hardwood Mixed Forest, Northern Japan

摘要

Regeneration traits of four dominant species were studied during a decade in a cool-temperate conifer-hardwood mixed forest, northern Japan. Dominant species were three canopy species ( style="font-family:Verdana;">Tilia japonica style="font-family:Verdana;">, style="font-family:Verdana;">Acer mono style="font-family:Verdana;"> and style="font-family:Verdana;">Abies sachalinensis style="font-family:Verdana;">) and a subcanopy species style="font-family:Verdana;">Prunus ssiori style="font-family:Verdana;">. Regeneration traits differed among the four dominant species. The regeneration of a conifer style="font-family:Verdana;">Abies sachalinensis style="font-family:Verdana;"> largely depends on major disturbances because its size structure was a bell-shaped pattern. The growth rate of the sub-canopy species style="font-family:Verdana;">Prunus ssiori style="font-family:Verdana;"> increased faster with tree size than the other three species, and therefore, this species can reach reproductive stage faster. Although the number of recruits of style="font-family:Verdana;">Tilia japonica style="font-family:Verdana;"> was less than the other three dominant species, about one-fourth of style="font-family:Verdana;">Tilia japonica style="font-family:Verdana;"> regenerated by the sprouts. Thus, vegetative reproduction is important for the regeneration of style="font-family:Verdana;">Tilia japonica style="font-family:Verdana;">. On the contrary, many recruits were observed in style="font-family:Verdana;">Acer mono style="font-family:Verdana;">, and its recruits and saplings concentrated in canopy gaps, suggesting that the regeneration of style="font-family:Verdana;">Acer mono style="font-family:Verdana;"> restricted to canopy gaps. Thus, clear differences in the regeneration traits were recognized in the four dominant species. This study suggests that the species-specific regeneration traits contribute to the species coexistence of the four dominant species through different regeneration niches.