Net production and carbon cycling in a bamboo Phyllostachys pubescens stand

Phyllostachys pubescens Mazel ex Houzeau de Lehaie is one of the largest bamboo species with a leptomorph root system in the world. The species originates in China and has been naturalized in the neighboring countries. It was introduced in 1746 into Japan because of the economic value of the young sprouts and culm woods. It escaped from the planted areas and expanded by invading the original vegetation. In order to clarify the basic ecological characteristics of the species, carbon fixation and cycling were determined in a stand of Phyllostachys pubescens. The standing culm density and average DBH in 1991 were 7100 ha(-1) and 11.3 cm, respectively. The above-ground biomass was 116.5 t ha(-1) for culms, 15.5 t ha(-1) for branches, 5.9 t ha(-1) for leaves and 137.9 t ha(-1) in total. The total above-ground biomass was one of the largest among the world's bamboo communities. The biomasses of rhizomes and fine roots were 16.7 t ha(-1) and 27.9 t ha(-1), respectively. Annual soil respiration was 52.3 t CO(2) ha(-1) yr(-1), the highest among those determined in Japan. The gross production was high: 32.8 t C ha(-1) yr(-1). Allocation of the products to its root system was also high: 34% to gross production and 46% to the fluxes out of the leaves into other compartments of the ecosystem. This resulted in the reduced above-ground net production of 18.1 t ha(-1) yr(-1), which fell within the average range of productivity of forests under similar climate conditions. This paper discusses the correspondence of the allocation pattern with the successful range expansion.