A model for the investigation of long-term carbon dynamics in boreal forests of western Canada. I. Model development and validation

To interpret field studies of forest floor dynamics in the continental boreal forest of western Canada and identify areas for future research, we developed a boreal forest carbon dynamics model based on the decay algorithms of the CENTURY model. Forest floor and mineral soil carbon pools were separately represented. We quantified detrital inputs for nine separate components of live vegetation using published data to relate litterfall to biomass and regression models to relate biomass of each component to stand age and other significant variables. The regression models were developed from observed C stocks of each component using data from 80 forest stands forming six chronosequences. The six chronosequences were for two of the principal species in this region, Pinus banksiana and Populus tremuloides, in each of three distinct climatic areas (approximately represented by the BOREAS SSA, BOREAS NSA and Wood Buffalo National Park). We carried out extensive sensitivity testing and validation tests against a wide range of data, including forest floor carbon stocks measured in the six chronosequences. The validation tests highlighted the need for better data in several areas, particularly root litter, woody detritus dynamics, coniferous foliage litter and nitrogen budgets. Nevertheless, the model performed well against the available data and was judged adequate for its purposes.