Study on Temporal and Spatial Characteristics of Precipitation Redistribution and Heavy Metal Elements at Pinus densata Forest in Sejila Mountain

Taking Pinus densata forest in Sejila Mountain as the research object, and combining positioning observation and indoor analysis, the elements of Fe, Mn, Zn, Cu and Cd of precipitation, throughfall and stem-flow were analyzed in the rainy season, which grasped the cycle characteristics of heavy metal elements in precipitation in P. densata forests. The results showed that interception of precipitation by P. densata forest was 19.70% to 38.82%. The throughfall accounted for 71.48% of precipitation, whereas the stem-flow accounted for 4.53% of precipitation. The order of pH value each water phase was: precipitation ≈ throughfall > stem-flow. In the precipitation, throughfall and stem-flow and various metal elements all were the peak of the rainy season> the beginning of the rainy season> the end of the rainy season. In the throughfall of rainy season, the net leaching of Cd was 0, and the net leaching of Fe and Zn was negative, respectively –0.005 mg/L and –0.008 mg/L. In the stem-flow, the net leaching of Cd was negative, –0.001 mg/L. The net leaching coefficients of each heavy metal element in the throughfall and stem-flow were respectively Mn> Cu> Cd> Fe> Zn, Zn> Cu> Mn> Fe> Cd. The input amount of each heavy metal element in the throughfall and stem-flow was less than the precipitation, especially stem-flow. The input amounts of Cd, Fe, and Zn were negative. The P. densata forest has an ability to absorb Cd, Fe, and Zn, and an leaching effect on other heavy metal elements.