Extensive comparison of purificatory function of environmental pollutants by forest ecosystems

为了评价森林生态系统净化环境污染物的功能，开展了广泛的对比研究。本文分析了北海道、京都崎阜、平阳山、日本高松、中国南部和泰国北部13个森林流域雨水和径流的水化学成分。根据温暖指数，这六个地区被分为冷温带、暖温带和亚热带。冷温带和亚热带地区径流水中主要溶解离子含量均低于暖温带地区。在岛根县，降雪中检测到高浓度的Na^+、Cl^-、NO_3^-、SO_4^<2- b>离子。然而，这些化学物质对径流水的影响尚未检测到。在山口县，分别测量了森林的湿降和干降。所谓的人造污染物在旱季中含量更高。采用重水和重氮对中国中部地区3种森林土壤的水力导电性进行了比较。通过对雨水和土壤中N的自然丰度的测量，证实了流域的反硝化作用。

Extensive comparison studies were carried out to evaluate the function of forest ecosystems to purify the environmental pollutant.1. Water chemicals of rain and runoff stream water from thirteen forested watersheds which are located in the area of Hokkaido, Gifu, Mt.Hiei in Kyoto, and Takamatsu in Japan, Southern China and Northern Thailand were analyzed.According to Warmth Index, those six areas are classified in cool-temperate, warm-temperate or sub-Tropical zones.Both in cool-temperate and sub-tropical areas, major dissolved ions in runoff water were low comparing with those in warm-temperate area.2. In Shimane prefecture, high concentration of Na^+, Cl^-, NO_3^-, SO_4^<2-> ions was detected in snowfall.However, the effects of these chemicals on runoff water were not detected.3. In Yamaguchi Prefecture, wet-and dry-fall to the forest was separately measured.So-called man-made pollutants were contained more in dry-fall.4. On the three kinds of forest soils in Chugoku area, the hydraulic conductivity was compared using heavy water and heavy nitrogen.5. Through the measurements of natural abundance of ^<15>N in rain and soil water, denitrification in the watersheds was confirmed.