14:30 〜 14:45
[ACG39-04] Simulating the effect of carbon starvation on the terrestrial ecosystem by using individual-based vegetation model SEIB-DGVM
キーワード：炭素飢餓、非構造性炭水化物、SEIB-DGVM、気候変動、炭素循環
Pervasive shifts in forest vegetation dynamics are already happening and are expected to accelerate under future global changes (McDowell et al., 2020). Forest dynamics are changing due to anthropogenic-driven drivers, such as rising temperature and CO2, and are affected by transient disturbances. Tree recruitment and growth depend on the changing drivers in a spatially and temporally way, potentially leading to an increase in tree mortality rates. Although a variety of stress and disturbances cause tree mortality, drought-induced mortality is considered one major cause of the recent widespread tree mortality events, which profoundly damage ecosystems and many ecological processes (Hendrik and Maxime, 2013; Anderegg et al., 2015).
Trees have grown to control their carbon resources to extend lives and strategically allocate them to growth, respiration, storage, reproduction, and defense (Henrik et al, 2018). Among carbon resources, non-structural carbon (NSC) is commonly considered a repository depending on the balance between the supply of assimilated carbon and carbon demand. Hence, the size of stored C pools can be considered an indicator of the carbon balance of the plant. Additionally, NSC could be the threshold of the conceptual “carbon starvation” as one of the mechanisms after drought (Hoch et al, 2003; McDowell et al., 2008). However, no ecosystem model can calculate the NSC dynamics clearly, thus it could prevent from understanding the biomass loss due to drought, even simulating the future carbon cycling. The objectives of the research are 1) to apply the process representing NSC dynamics to the ecosystem model, 2) to simulate the effect of carbon starvation on forest dynamics, carbon cycling, and vegetation distribution by using the ecosystem model including the NSC accumulation process.
The process-based Spatially Explicit Individual-Based Dynamic Global Vegetation Model (SEIB-DGVM; Sato et al., 2007), representing three-dimensional tree structure and individual tree growth, is used in this study. In a 30m×30m grid, each plant competes with the other for incoming solar photons. Then, a process of accumulating NSC in tree bodies for SEIB-DGVM is newly made, and the new NSC function is validated at 4 observation sites, and on a global scale, and we analyzed how the model outputs from the new model are different from them from the original SEIB-DGVM. Moreover, the new model is calculated from 1850 to 2100 to understand the future carbon cycle. We simulated the region, climate, and biome types that are vulnerable to carbon starvation by analyzing the difference of NSC change between historical scenarios and future scenarios. The study could improve understanding of how carbon starvation will affect the forest dynamics, vegetation distribution, and woody biomass in the future.
Trees have grown to control their carbon resources to extend lives and strategically allocate them to growth, respiration, storage, reproduction, and defense (Henrik et al, 2018). Among carbon resources, non-structural carbon (NSC) is commonly considered a repository depending on the balance between the supply of assimilated carbon and carbon demand. Hence, the size of stored C pools can be considered an indicator of the carbon balance of the plant. Additionally, NSC could be the threshold of the conceptual “carbon starvation” as one of the mechanisms after drought (Hoch et al, 2003; McDowell et al., 2008). However, no ecosystem model can calculate the NSC dynamics clearly, thus it could prevent from understanding the biomass loss due to drought, even simulating the future carbon cycling. The objectives of the research are 1) to apply the process representing NSC dynamics to the ecosystem model, 2) to simulate the effect of carbon starvation on forest dynamics, carbon cycling, and vegetation distribution by using the ecosystem model including the NSC accumulation process.
The process-based Spatially Explicit Individual-Based Dynamic Global Vegetation Model (SEIB-DGVM; Sato et al., 2007), representing three-dimensional tree structure and individual tree growth, is used in this study. In a 30m×30m grid, each plant competes with the other for incoming solar photons. Then, a process of accumulating NSC in tree bodies for SEIB-DGVM is newly made, and the new NSC function is validated at 4 observation sites, and on a global scale, and we analyzed how the model outputs from the new model are different from them from the original SEIB-DGVM. Moreover, the new model is calculated from 1850 to 2100 to understand the future carbon cycle. We simulated the region, climate, and biome types that are vulnerable to carbon starvation by analyzing the difference of NSC change between historical scenarios and future scenarios. The study could improve understanding of how carbon starvation will affect the forest dynamics, vegetation distribution, and woody biomass in the future.