通过分析土壤理化性质，了解西天目山土壤理化性质的变化并验证酸沉降导致近年来西天目山柳杉衰退的观点.沿海拔梯度从350~1 350 m每隔200 m选定取样点，每个样点分3层取土样，分析土壤的理化性质.总体来看，随着海拔的升高，粗颗粒比例、土壤含水量和有机物含量增加，土壤容重和pH值随海拔的升高而降低，而总氮和总磷含量没有固定的趋势.与11年和20年前相比，土壤pH值显著降低，表明土壤呈现明显的酸化，土壤的快速酸化提供了酸沉降诱发柳杉快速衰退的证据.
In recent years, ancient trees of Cryptomeria japonica var sinensis in Western Tianmushan are declining due to attacks by diseases and insect pests, which were believed to be triggered by acid deposition. The physical and chemical features of soils to provide references for this opinion was analyzed. In this study, soil samples were collected along altitude from 350 m to 1 350 m, with the interval of 200 m. At each sampling site, soil samples were collected from three layers. Soil texture, humidity, bulk density, pH value, organic matter content, contents of total nitrogen and total phosphor were analyzed. Generally, percentage of coarse particles, soil humidity and organic matter content increased with increasing altitude. Soil bulk density and pH value had a declining trend with the increase in altitude. Total nitrogen and phosphor contents had no constant trend along altitude. Compared to the data of 1986 and 1995 years, significant decrease in pH value was observed, indicating a trend of acidification. The observed soil acidification provides evidence for the rapid decline in ancient trees of Cryptomeria japonica var. sinensis triggered by acid deposition.