Preliminary Investigation on the Role of Chinese Arborvitae Forests in Composition and Redistribution of Rain and Snow and Suspended Particulate Sink near Urban Area of Jinan

Cation concentrations and element composition of rain and snow samples collected from forests of Chinese arborvitae (Platycladus orientalis (L.) Franco) in 1999 were analyzed by HPIC, ICP-MS, and ICP-AES. The pH value and electrical conductivity, as two main indicators, were also measured. Significant difference was found in electrical conductivity, element concentration, and cation concentration between stem flow, bulk, and through fall.Ca²⁺ concentration in stem flow, for instance, reached 150.7 mg·L^-1, whereas that of bulk and throughfall was 66.4 mg·L^-1 and 119 mg·L^-1, respectively. Electrical conductivity was 962 μs·cm^-1 in stem flow, and 560 μs·cm^-1 in bulk. Comparison made between snow and rainwater shows that pH, electrical conductivity, cation concentration and element content in snow were lower than those of rain. For example, the mean pH of rainwater was 6.9, whereas that of snow at the same site (Xihe)was 4.86. A great amount of suspended particulates which deposited on leaf surface was found with the analysis of washing solution.Total deposition of Ca²⁺, Mg²⁺, K⁺, and Na+ on leaf surface reached 35.87 kg·hm^-2,which reveals the role of Chinese arborvitae forest in suspended particulate sink.