Redistribution characteristics of atmospheric precipitation in different spatial levels of Guangzhou urban typical forests in southern China

Özet

The aims of the present study were to determine the pH variation and chemical feature of atmospheric precipitationduring the research period. We also investigated the redistribution characteristics of rainfall whilepassing through the canopy layer, leaf-litter layer and soil layer, successively to quantify the acid rain bufferingcapacity of these spatial levels in the evergreen broadleaved forest (EBF), deciduous broadleaved forest (DBF)and coniferous forest (CF) in Guangzhou urban area, China. Results showed that the rainfall was typically acidic,and the acid rain type in Guangzhou urban area is converted from sulfuric acid type to mixed type of sulfuricacid and nitric acid. The major ions from the canopy to the forest floor differed within the three forest types.However, the enrichment phenomenon of base cations in soil leachate in EBF and DBF implied that nutrient losswas more serious in the broadleaved forest than in the coniferous forest. Variability of ionic concentration andpH in the vertical sequence of different tree species showed that the net ion concentration variation index has asignificant conic relationship with ne pH change rate. We also built an acid rain buffering index, which combinesthe neutralization and interception effects of vegetation to acid rainfall. The present results indicated that thethree forest types in urban Guangzhou all have certain buffering capacity to acid rain, and following the order:DBF > EBF > CF. In the meanwhile, the forest canopy is the biggest acid rain buffer in urban Guangzhou,following by the soil.