As a major part of terrestrial ecosystem, forest plays an important role in ameliorating global changes resulted from green- house-gas release. The uncertainty in carbon balance of forest soil is the key factor limiting our understanding to this effect. The soil organic carbon accumulates along with forest succession. A better understanding in the role of fine roots in carbon balance is needed. The old Korean pine forest on Changbai Mountain is a temperate zonal climax forest and it is important in estimation of carbon fixing potential of temperate forests.

Fine root turnover is a regulating factor in soil carbon cycling and storage. The fine root production and dynamics is important in understanding global carbon balance. For this reason, the research team of Interface Ecology in IAE, supported by a Key project of NNSFC and a National 863 Project, constructed multifactor field experiment platform concentrating to studies in the process, mechanisms and methodology in carbon fixation by temperate forest ecosystem under the background of global changes. The environment factors such as  carbon, nitrogen, water and temperature were all monitored or regulated. The research has got a series important advancement.

Six successive year investigation showed that fine root biomass, production, dead mass and disappeared mass had apparent seasonal variations. The biomass is correlated to the average temperature and rainfall of previous month. The monthly fine root production is closely related to the average temperature of the current month. The seasonal variation pattern of fine root production is similar to that of forest net primary production (NPP) but to that of litter fall. The total fine root production is 25% of the forest NPP. The carbon input into soil is 1.2 times of that by litter fall.  

The fine root biomass of Broadleaved Korean Pine Forest was decreased by 47% and fine root turnover rate increased by simulated Nitrogen fertilization and water limitation.In 0-10cm top zone of soil profile, N availability is the main factor affecting the structure of fine roots. In the zone 10-20cm, the growth and structure of fine roots are affected by the combined effect of water and N availability.

These results illustrated the effect of water and nitrogen precipitation on the dynamics of fine roots in Broad-leaved Korean Pine Forest, estimated the contribution of fine roots to soil carbon pool and provides data for further quantification of carbon fixation rate and potential of China’s temperate forest ecosystem.

The results were published in Plant and Soil (Wang et al., 20 16, 400(1): 275-284 and Plos ONE (Wang et al., 2012, 7 (3): e31042)