Modelled net carbon gain responses to climate change in boreal trees: Impacts of photosynthetic parameter selection and acclimation

摘要: Boreal forests are crucial in regulating global vegetation-atmosphere feedbacks, but the impact of climate change on boreal tree carbon fluxes is still unclear. Given sensitivity vegetation models to photosynthetic and respiration parameters, we determined how predictions net gain (C-gain) respond variation these parameters using a stand-level model (MAESTRA). We also modelled thermal acclimation respiratory temperature alters predicted C-gain responses change. seven common species under eight scenarios across latitudinal gradient capture range seasonal conditions. Physiological parameter values were taken from literature together with different approaches for thermally acclimating photosynthesis respiration. At high latitudes, was stimulated up 400% by elevated temperatures CO2 autumn suppressed at lowest latitudes during midsummer that included warming. Modelled more sensitive capacity (Vcmax , Jmax Arrhenius response ratio Vcmax ) than stomatal conductance or parameters. The effect depended where it applied: reduced 10%-15% within equations derived decreased 175% outside this range. Thermal had small, positive, impacts C-gain. show simulations highly highlight need better understand mechanisms drivers underlying variability (e.g., whether environmentally and/or biologically driven) further improvement.