Effects of tree species and fallen trees on the soil properties in a temperate Korean pine and broad-leaved mixed forest

This paper focused on the temperate Korean pine and broad-leaved mixed forest of Changbai mountain,and investigated on the soil properties of forest floor influenced by old-growth trees or fallen trees in the direct vicinity.The results indicated that different tree species have significant effects on the soil properties of forest floor in current experimental plot.The water-soluble organic carbon(WSOC) and the specific ultra-violet absorbance(SUVA254) of forest soil in the vicinity of Pinus koraiensis were higher than that of Tilia amurensis and Fraxinus mandshurica;but as to water-soluble total nitrogen(WSTN) and exchangeable inorganic nitrogen,it was higher in Tilia amurensis and Fraxinus mandshurica,and lower in Pinus koraiensis.The study of soil properties of forest floor influenced by fallen trees indicated that forest soil under fallen tree had greater content of WSOC,WSTN and exchangeable inorganic nitrogen than that of forest soil in interstem-areas.The results suggested that the fallen trees would be important sources of active carbon and nitrogen of forest soil,at least in the small-scale space.Moreover,the relevance among soil properties influenced by different tree species was investigated by using principal component analysis,and the possible mechanism involved in soil properties affected by tree species and fallen trees in the direct vicinity was also discussed.