Tree Physiology · 1991 · 316 citations · 0 references
Natural SciencesEcologySoil SciencesBiogeochemistryNutrient CyclingTerrestrial EcologyBiogeochemical Cycle ModelingCarbon AllocationCarbon CycleCarbon CyclingNitrogen CycleNitrogen CyclingBelowground Biomass AllocationBiomass Carbon StorageC:n:p StoichiometryCarbon Cycle ModelingSoil Organic Carbon TurnoverStem Biomass AllocationTerrestrial Carbon-nitrogen InteractionsVegetation Carbon Storage
Terrestrial ecosystems respond to changes in CO₂, climate, and N deposition through enzymatic shifts, tissue stoichiometry changes, biomass allocation, soil organic matter turnover, N mineralization, and redistribution of C and N between vegetation and soils. The study develops a biogeochemical model to simulate C and N cycles and uses it to examine how CO₂, temperature, and N inputs influence carbon storage in arctic tundra and temperate hardwood forest. The model is a highly aggregated, process‑based biogeochemical model that simulates C and N fluxes and allocation among foliage, fine roots, stems, and soils in response to variations in CO₂, temperature, soil water, irradiance, and inorganic nitrogen inputs. The model predicts qualitatively similar responses in arctic tundra and temperate hardwood forest, but quantitative differences arise from initial C and N distribution, woody tissue amounts, and relative N limitation, and the authors discuss the model’s strengths, weaknesses, and future directions.
A model that simulates carbon (C) and nitrogen (N) cycles in terrestrial ecosystems is developed. The model is based on the principle that the responses of terrestrial ecosystems to changes in CO(2), climate, and N deposition will encompass enzymatic responses, shifts in tissue stoichiometry, changes in biomass allocation among plant tissues, altered rates of soil organic matter turnover and N mineralization, and ultimately a redistribution of C and N between vegetation and soils. The model is a highly aggregated, process-based, biogeochemical model designed to examine changes in the fluxes and allocation of C and N among foliage, fine roots, stems, and soils in response to changes in atmospheric CO(2) concentration, temperature, soil water, irradiance, and inorganic nitrogen inputs. We use the model to explore how changes in CO(2) concentration, temperature, and N inputs affect carbon storage in two ecosystems: arctic tundra and temperate hardwood forest. The qualitative responses of the two ecosystems were similar. Quantitative differences are attributed to the initial distribution of C and N between vegetation and soils, to the amounts of woody tissue in the two ecosystems, and to their relative degree of N limitation. We conclude with a critical analysis of the model's strengths and weaknesses, and discuss possible future directions.