Impact of logging on carbon density of broadleaved-Korean pine mixed forests on Changbai Mountains Spatiotemporal dynamics of seed rain in a broadleaved-Korean pine mixed forest in Xiaoxing′an Mountains, China EFFECTS OF SOLAR RADIATION ON NET ECOSYSTEM EXCHANGE OF BROADLEAVED-KOREAN PINE MIXED FOREST IN CHANGBAI MOUNTAIN, CHINA Spatial heterogeneity of soil inorganic nitrogen in a broadleaved-Korean pine mixed forest in Changbai Mountains of Northeast China