FOREST DECLINE IN NANSHAN, CHINA

In Nanshan, the south suburb of Chongqing city in China, there are about 2000 ha of masson pine forest (Pinus massoniana Lamb.) which has exhibited decline since the beginning of the 1980s. About 85% of pine trees are injured to varying degrees, and one-third have died. In order to investigate the causes of decline, three monitoring sites were selected. At two sites pine trees were severely injured. At another site furthest from the city they showed approximately normal growth. AtmospheriC SO2 and fluoride concentration, and the sulphur and fluorine content of pine needles at these three sites were monitored. The intensity of damage to masson pines was consistent with an increase in the atmospheric concentrations of SO2 and fluoride, and also in the sulphur and fluorine content of needles. It was suggested that the combination pollution of SO2 and fluoride might be the major cause of the decline of masson pines in Nanshan. The effect of acid rain, acid fog and pests on the pine forest are also discussed.