Abstract
To evaluate the influence of the long-range transported atmospheric pollutants on the vegetation, we measured the dry deposition of anions and leaching of cations from the needles of two pine species, Pinus armandii var. amamiana (Paa) on Yakushima Island and Pinus dendiflora Sieb. et Zucc. (Pde) on the Kirishima mountains, southwestern Japan. In both species, we found the dry deposition on 1-year-old needles more than on current-year ones. We detected F- in the dry deposition on the needles of Paa, suggesting that F- originated from China based on the results of a back trajectory analysis, because atmospheric F- was detected at higher concentration in China. We found Ca2+ and Mg2+ besides K+ in the leachate from both species, suggesting that these cations were leached from the cytoplasm after degradation of the needles’ surfaces. The dry deposition of anions and leaching of cations were strongly correlated (r=0.71-0.96, p<0.01) in Paa. However, we found no significant correlations between the dry deposition and leaching in Pde. Our results suggest that dry deposition was the main cause of the increased leaching from the needles of Paa, whereas other factors were more important for Pde. In addition to the dry deposition, photochemical oxidants may negatively affect these pine species in these natural habitats.
