Comparative study on water source separation among co-occurring plants

Abstract

To reveal the effect of competition for water on water use pattern of Pinus densiflora, comparative observations of water uptake zone of co-occurring plants were carried out at four sites in Sugadaira Highlands, central Japan. Water uptake zone was determined by the isotopic tracer method. We found that the P. densiflora and Sasa senanensis took up water from the 10-40 cm depth zone, Malus sieboldii from 10-20 cm depths, and Populus sieboldi from 60-80 cm depths. Water uptake zone of P. densiflora was invariable even if co-occurring species are different. Thus, we concluded that water use pattern of P. densiflora in Sugadaira Highlands is not affected by inter-specific competition, while M. sieboldii and P. sieboldi may reduce water stress by the water source separation.