Distribution of soil carbon stocks in Canada's forests and wetlands simulated based on drainage class, topography and remotely sensed vegetation parameters

Abstract A quasi‐three‐dimensional hydrological model was developed and integrated into the integrated terrestrial ecosystem carbon‐budget model (InTEC V3·0) to improve the estimation of the carbon (C) dynamics in Canadian forests and wetlands. Climate, soil, digital elevation map, and drainage class data, in conjunction with remotely sensed vegetation parameters, including leaf area index, land cover type, and stand age, are used to drive the model. Soil is divided into three layers, for which temperature and moisture dynamics are simulated. Individual 1 km × 1 km pixels are hydrologically linked with neighbouring pixels through subsurface saturated base‐flow, which is simulated using a TOPMODEL‐based scheme. Soil C and nitrogen (N) dynamics are simulated using the soil submodel of CENTURY suitably modified for forests and wetlands. The interannual variation in net primary productivity is iteratively computed after integrating the effects of N, climate, stand age and atmospheric CO 2 concentration on productivity. Compared with data in the Soil Landscape of Canada, the newly updated InTEC V3·0 can capture 66·6% of spatial variations in soil C and effectively alleviate soil C underestimation in wetland areas from its predecessor (InTEC V2·0) by considering the lateral water flow and the water table variation. Copyright © 2005 John Wiley & Sons, Ltd.