鈴鹿山系朝明川源流域ブナ林のオゾン濃度調査

抄録

The beech forest around the headwaters of the Asaka River in the Suzuka Mountains is the largest in the mountain range and plays a valuable role in terms of water source conservation, slope stabilization, ecosystem conservation, and tourism resources. In this study, the ozone concentration of the atmosphere in the beech forest was measured by the Ogawa type passive samplers. The ozone near the ground level is known to give bad effects on plant growth, and the index AOT40 is widely utilized to evaluate the level of ozone effect. The results of this study confirmed that ozone concentrations rise at around 2 ppbv/100 m along the mountain slopes, and that ozone reaches its maximum from April to May (monthly average concentration of around 60 ppbv). The concentrations were found to be similar to or higher than those found near the summits of the Tanzawa Mountains, which are known for the large-scale beech dieback. Using hourly ozone data at the foot of the mountain and the ratio of ozone concentrations between the foot of the mountain and the beech forest obtained by passive samplers, the cumulative AOT40 (12h) for the April-September period was estimated, and it was shown that there is a possibility that it could reach 40 ppmv・h, far exceeding the 10 ppmv·h that begins to cause damage to beech trees.