广州帽峰山常绿阔叶林森林生态系统水文环境效应

Effects of Hydrological Environment on Tropical Evergreen Broad-leaved Forest in Maofengshan Mountain of Guangzhou

对帽峰山季风常绿阔叶林的穿透雨、树干径流和大气降水及地表总径流水的pH值和Pb、Cu、Cd、Hg、Zn等重金属平均质量浓度进行测定,分析森林对水文的环境效应。结果表明:常绿阔叶林的穿透雨和树干径流的pH平均值比大气降水高了约1个pH值单位,最高可达2.6个pH值单位。树干径流的pH平均值比穿透雨的pH平均值要高,说明树干径流对酸雨的中和效应更为明显。大气降水中重金属平均质量浓度基本是旱季大于雨季,5种重金属的平均质量浓度次序为Zn>Cu>Pb>Cd>Hg。与大气降水相比,穿透雨和树干径流的重金属总体变化是雨季呈降低趋势,变化幅度一般在8.13%～49.38%;但在旱季这一趋势刚好相反。穿透水、树干径流对大气降水的淋溶系数的大小排列为:Pb>Cu>Cd>Hg>Zn。穿透雨淋溶系数都大于树干径流的淋溶系数,总体来说,穿透水对总金属元素的淋溶作用大于树干径流。

An experiment was conducted to study the effects of forests on hydrological environment in terms of pH value and contents of Pb,Cu,Cd,Hg and Zn elements in the samples of precipitation,throughfall,stemflow and surface runoff in Maofengshan Mountain,Guangdong Province. Results showed that the average pH value of throughfall was 1.0 pH unit higher than that of rainfall,with the highest value of 2.6 pH units. That is to say,the effect of neutralizing acid rain for forest canopy is significant. The average content of heavy metal in precipitation was higher in dry season than in rainy season,and the average contents of five kinds of heavy metals were in a decreasing order of Zn,Cu,Pb,Cd,and Hg. The average content of heavy metal in throughfall and stemflow in rainy season exhibited a downward trend compared with that in precipitation,ranging from 8.13% to 49.38%; but there was an upward trend in dry season. The order of leaching ability of throughfall and stemflow showed Pb 〉Cu〉Cd〉Hg〉Zn. The leaching coefficient and leaching ability of throughfall are higher than that of stemflow on the whole.