Effects of Air Pollution and Acid Deposition on Three Pinus densiflora (Japanese Red Pine) Forests in South Korea

Although a large area of forest damage due to acid deposition have not yet been found in South Korea, but some of local tree declines have been frequently reported especially for Pinus densiflora (Japanese red pine), the most common coniferous tree. In the present study, we evaluated the effects of acid deposition on forest, results of ambient SO2, acid load, soil pH and tree decline monitored from 1988 to 2001 in urban, industrial and mountainous area along the gradient of atmospheric pollution were compared. During the study period, annual mean SO2 concentrations in urban area averaged 13ppb with a maximum of 31ppb, 1989 and industrial and mountainous area averaged 14ppb and 6ppb, respectively. Annual mean acid loads were 0.09 and 0.11 kmol H+ ha-1 in urban and industrial area, significantly comparable with 0.03 kmol H+ ha-1 in mountainous. The surface soil of the red pine forest in urban and industrial area was acidified (pH 4.1-4.3), whereas pH 5.4 in mountainous area. On the other hand, based on defoliation and discoloration measured in l996 and 2001, decline degree of the pine trees in two polluted areas was higher than that in mountainous area. The data indicate that the combined effects of high air pollution and acid deposition-induced soil acidification (possibly Ca deficit and Al toxicity) could adversely influence the Japanese red pine.