Host: The Japanese Forestry Society
Dynamics of the undergrowing bamboo, Sasa kurilensis population was investigated for 8 years after mass flowering and death, with special reference to behavior of the unflowered patches. Sasa species often dominate in the undergrowth of the forests in the cool-temperate and boreal zones in Japan. Mass death of Sasa provides the chance for tree species to regenerate.
In 1995, S. kurilensis flowered to die over thousands ha near the Lake Towada, northern parts of Japan. We set a 1 ha permanent plot (Kougakudai Plot) to observe the dynamics of the beech forest after mass death of S. kurilensis in 1996. There were non-flowered S. kurilensis population among the flowered population. The total area of non-flowered patches was 0.41 ha within the 1-ha plot in 1996. However some of these population flowered several years after mass flowering. Twenty-one percent of the non-flowered population had been died till 2003.
Although Sasa species are reported to produce tens of thousands of seeds when they flowered simultaneously in the wide range, they produce few seeds in the small-scale flowering. In Kougakudai Plot, mean seedling density after mass flowering was 25.6 / m2 in 1996. However we hardly observe the seedlings in the later flowered populations. Vegetation dynamics in such patches may be different from that in the mass flowered population, because other species can grow without the competition with Sasa seedlings in such patches.
