Ecological Studies of Sasa Communities

I. Productive Structure of Some of the Sasa Communities in Japan

Abstract

Many species of “Sasa” (bamboo grasses) are distributed endemically in Japan. They often constitute the characteristic grassland communities or the shrub strata of open forests in montane and subalpine zones (or cool temperate or subarctic zones). This study was carried out on closed communities of different dominant Sasa species at four stations of the central Honshu and of Hokkaido.
1. Descriptions as to temperatures, precipitations and soil conditions were given as the basis of further discussion of Sasa communities.
2. The characteristics of the communities were investigated by the stratifying clip method in the weight of leaves, culms, subterranean parts and of entire plants, the height of community, the number of culms, the productive structure, the leaf area index, etc.
3. Among the communities with different dominant species and different localities, marked differences were realized in standing crop, height of community, longevity of culms, and number of culms. The standing crop increased with longevity of culms and height of community, and it is similar to or larger than the standing crop of other herb communities.
4. The amount and vertical distribution pattern of leaves of these Sasa communities were more or less the same. The leaf area index was 4.5-5.4, the extinction coefficient of light in the community, 0.7-0.9, and the light transmissibility of a leaf was about 10%.
5. On the ground surface of these Sasa communities, there prevailed extremely low light intensities with small deviation, enough to be fatal against seedlings of many species.