Effects of selection cutting on forest dynamics in the Shiretoko National Forest: Stand condition and regeneration pattern, five years after the cutting

Selection cutting was carried out in the Shiretoko National Forest from April 14 to April 16, 1987. This cutting received considerable public attention through mass media. This controversy implies financial problems in the Japanese National Forestry System, promotion of rural development, conflicts between wildlife and forest management, and effects of selection cutting on natural regeneration. Long monitoring data of stand dynamics is necessary to discuss this type of controversy scientifically. We set up permanent plots in selection cutting stands of Shiretoko National Forest four months after the cutting to examine stand structure. Five years later, we investigated the same plots again to monitor stand dynamics. As a result of this research, following was estimated for the trees taller than 2m. 1) Cutting patches in 1987 were not uniformly distributed over all the stands, rather it concentrated in some stands. Cutting reached 27.1% in basal area in the developed stand consisting of large Quercus mongolica var. grosseserrata trees. 2) The number of trees decreased for five years in all plots, whereas volume increased by 20% in comparison with that in 1987. 3) Disappearance rates were not significantly different among plots. Small sized deciduous trees disappeared in all plots. 4) Trees growing more than 2m in five years were predominant in the plot which received intensive cutting. Crown opening by cutting had a particularly pronounced effect on the height growth of Abies Sachalinensis. 5) A significant difference in diameter growth was not recognized among the plots. The results for seedlings shorter than 2m were as follows. 1) Sproutings from stump dominated crown opening site where large Quercus mongolica var. grosseserrata trees were cut. These sproutings disappeared for five years, and new ones sprouted from the stump. Seedlings established in the openings in 1987 also disappeared in five years, and new seedlings were reestablished. This indicated that both Quercus mongolica var. grosseserrata sproutings and seedlings repeatedly appear and disappear over short periods of time. 2) In terms of Abies Sachalinensis, relatively tall seedlings growing under the crown openings indicate a high survival rate. These seedlings grew faster than those under the crown closures. This indicated that Abies Sachalinensis may become a gap successor which fills crown openings in the future