Simulation study of the vegetation structure and function in eastern Siberian larch forests using the individual-based vegetation model SEIB-DGVM

The global ecosystem model SEIB-DGVM was adapted for an eastern Siberian larch forest through incorporation of empirical rules of allometry, allocation, and phenology developed for a larch stand at the Spasskaya-pad tower site, Yakutsk, Russia. After calibration, the model reconstructed post-fire successional patterns of forest structure and carbon cycling. It also reconstructed seasonal changes in carbon, water, and energy cycling in a mature larch forest. Sensitivity analysis showed that simulated functional properties of forest (LAI, NPP, carbon pools, and water runoff) are mainly determined by climatic environment, and population dynamic parameters (i.e., parameters for establishment and mortality) plays only minor role on them. Sensitivity analysis also showed that plant productivity and biomass were mainly limited by available water at Spasskaya-pad, where mean annual precipitation is only 257 mm. In the model, higher air temperature increases plant productivity via extension of growing season, and decreases plant productivity via causing drought and higher respiration. We found that the net effect is reduction of productivity, suggesting a possibility that global warming induces decrement of plant productivity in eastern Siberian larch forests.