Spatiotemporal Variations in Biomass Carbon Storage for Three Forest Management Regimes in Northeast China

Forests, which account for 76~98% of terrestrial plant carbon and 2/3 of terrestrial carbon sequestration in the world every year, can store or release large amounts of carbon as a result of natural environmental variability and human activities. Quantifying the spatiotemporal dynamics of forest biomass carbon storage is important not only for understanding the role of forests in global warming but also in supporting decision-making processes in forest management. We established biomass-volume models utilizing investigation data of sample plots in the Luishuihe forest area of Northeast China. Based on the models and a forest resource inventory database, forest biomass carbon storage at Lushuihe in 1987, 1995, and 2003 was estimated and mapped in a geographic information system (GIS). The forest biomass carbon storage in areas with 3 different management regimes during different time periods was also obtained based on area maps and maps of carbon storage in the GIS. The results showed that both carbon storage and density first decreased between 1987 and 1995, and then increased between 1995 and 2003. Such temporal dynamics of forest biomass carbon storage corresponded well to changes in Chinese forest policies. Forest biomass carbon storage and density of natural forests in key ecological welfare forest (EWF) areas, where harvesting is prohibited, steadily increased between 1987 and 2003 due to the prohibition of timber harvesting. Decreases in forest biomass carbon storage and density of natural forests in ordinary EWF areas, where harvesting is allowed under certain presumably beneficial conditions, were much less from 1995 to 2003 than from 1987 to 1995 due to decreased timber harvesting. In commodity forest (CoF) areas these decreases in natural forests were also less from 1995~2003 than 1987~1995 due to decreased timber harvesting. The area and biomass carbon storage of plantations in the 3 areas steadily increased between 1987 and 2003. The rate of decrease of carbon density in CoF areas was even less than that in local EWF areas because the area and carbon storage of fast-growing plantations in CoF areas were much greater than these in local EWF areas from 1995 to 2003.