杉木光皮桦混交林效益的研究

对桂西北杉木光皮桦混交林和杉木纯林的对比研究表明，35年生杉桦混交林的立木蓄积量为441.087 m3*hm-2，比杉木纯林高3.6%。混交林枯枝落叶层现存量及其N,P,K,Ca,Mg等元素的质量浓度分别为13.18 t*hm-2，158.3，6.1，16.5，86.3和32.3 kg*hm-2，分别比杉木纯林高9.7%，76.7%，69.4%，96.4%，83.2%，17.0%。混交林地(0～100 cm)土壤容重为0.81～1.22 g*hm-3，比杉木纯林低1.0%～8.0%，而土壤孔隙度，通气度和持水量分别比杉木纯林高2.0%～3.9%。土壤有机质、全氮、水解氮、有效磷和速效钾分别比杉木纯林高5.5%～49.8%。

Benefits in Mixed Forest of Cunninghamia lanceolata and Betula luminifera

Comparative studies were conducted on mixed forest of Cunninghamia lanceolata and Betula luminifera and pure Cunninghamia lanceolata forest in westren of Guangxi.The result showed that the growing stocks in stands of 35-year-old mixed forest was 441.087 m3*hm-2,which was by 3.6% higher than those of the same years old forests of pure Cunninghamia lanceolata.The mean standing crop of litteron forest floor in mixed forest was 13.18 t*hm-2 and the mass concentration of N,P,K,Ca,Mg were 158.3,6.1,16.5,86.3,32.3 kg*hm-2,respectively.Being by 9.7%,76.7%,69.4%,96.4%,83.2%,17.0% higher than that of pure Cunninghamia lanceolata forest,respectively.In mixed forest,the soil volume weight (0～100 cm) were 0.81～1.22 g*cm-3,were 1.0%～8.0% lower than that of pure Cunninghamia lanceolata,but it total poresity aeration porosity and moisture capacty were 2.0％～3.9％ higher than that of pure Cunninghamia lanceolata,respectively.The nutrientconcentration of organic matter,TN,hydrolazable N,available P and repidly available K in the soil,being by 5.5%～49.8% higher than that of pure Cunninghamia lanceolata,respectively.