RAINFALL PARTITIONING INTO THROUGHFALL AND STEM-FLOW AND RELATED BASE CATIONS FLUXES: SUCCESSION IMPACTS IN SUBTROPICAL REGION OF EASTERN CHINA

摘要

The goals of present study were to quantify rainfall partitioning and related base cations in three successional stages of evergreen broad-leaved forests across wet and dry seasons in the Tiantong National Forest Park, eastern China. Of incident precipitation, 78% became throughfall in primary forest while 55 and 66% of gross precipitation became throughfall in secondary forest and secondary shrubs, respectively. Stemflow amounts represented 6-14 % of the incident rainfall. Based on canopy budget model, canopy exchange of K and Mg was often more dominant than dry deposition. K was the most enriched with enrichment factors of up to 5 and 11 for throughfall and stemflow, respectively. By contrast, Ca was always taken up by the canopy and the stem. Values of nutrient deposition were high with value of 9.4, 5.0, 1.0 and 2.4 kg ha~(-1) month~(-1) in stand deposition of Ca, K, Mg and Na, respectively in secondary shrubs, possibly due to high tree density and richness. This research discussed the impacts of sere stages on precipitation partitioning and related base cations.