Abstract: [Objective] Understanding the distribution characteristics and accumulation of soil organic carbon and components from different successional series of broadleaved Korean pine forests in Xiaoxing'an mountains of China, would facilitate accurate evaluation of the forest ecosystem carbon reserves and function of soil carbon and carbon sequestration potential.[Method] The temporal-spatial substitution method was used to study the total soil organic carbon, readily-oxidized organic carbon (ROC), resistant carbon (RC), mineralization carbon (MC) and dissolved organic carbon (DOC) contents of the mixture of broadleaved trees and Korean pine with three different succession series (xerosere, mesosere, hydrosere) and the contribution rate of each composition for TOC. Then the key factors for controlling soil organic carbon and its components were analyzed with Pearson correlation analysis.[Result] The total carbon content of different successional series of broad-leaved trees and Korean pine forest in Xiaoxing'an mountains was characterized by hytroseres series > mesoseres series > xeroseres series. The total soil organic carbon tended to decrease with the depth of soil profile, that is 40-60 cm soil layer > 40-20 cm soil layer > 10-20 cm soil layer > 0-10 cm soil layer. The RC of the three succession series contributed to the TOC were 34.42%, 13.27%, 12.17%, the contribution of DOC to the TOC were 0.09%, 0.07% and 0.08%, the ROC contributed to the TOC were 33.59% 65.18%, 54.53%, and the MC contribution to the YOC were respectively 0.58%, 0.53%, 0.37%. The TOC was positively correlated with the MC, ROC and RC (P<0.01), RC was significantly related to MC, DOC, and negatively correlated with the content of ROC (P<0.01). The TOC content was affected by total soil nitrogen (P<0.01) and soil water content (P<0.01), and the RC showed significant positive correlation with total nitrogen (P<0.01)and significant negative correlation with the ratio of sand, and the content of MC was negatively correlated with soil pH (P<0.01) and positively correlated with soil water content and litterfall (P<0.01). The relationship between the content of ROC and the content of DOC was not significantly related to the soil factors.[Conclusion]There were significant difference of soil organic carbon and its components from different successional series of broadleaved trees with Korean pine forest. Community successional time and physical and chemical properties of soil led to difference of soil organic carbon and its components.

Key words: broad leaved korean pine forest, successional series, soil organic carbon, fraction, characteristics