Publicly Offered Research
Grant-in-Aid for Transformative Research Areas (A)
Reliable projections of future forest carbon dynamics are needed owing to the role of forest in the global carbon budget. The isotope composition of tree rings provides information on the physiological response of forests to changes in atmospheric CO2 and climate. We will compare simulation using a multi-layer ecosystem gas exchange model parametrised with long-term series of δ13C, δ18O and δ2H in tree rings with 20-year data of stand-level CO2 and water fluxes, and 50-year data of evapotranspiration calculated from watershed hydrological data.
Clear and divergent temporal patterns were observed for 13C, 18H and 2H of cellulose extracted from 796 tree rings (80-year series) cut from wood cores collected on 14 trees the Kiryu experimental watershed.13C was very sensitive to change in canopy structure while 18O was less, highlighting an increase in tree photosynthesis after stand harvest in 1960, likely due to reduced competition. The trend in 13C after 1980 likely results from the increase atmospheric CO2 concentration. Difference in 13C between old and young trees are likely due to higher light absorption by the crown of old trees rather than hydraulic constrains.Leaf water enrichment in 18O can be predicted satisfactorily but predicting wood cellulose 18O is challenging.Despite the huge amount of data are still under analysis, the results demonstrates that tree ring isotopes integrate physiological response to changes in the environment (atmospheric CO2, climate, resource availability) and forest structure.
令和5年度が最終年度であるため、記入しない。
All 2024
All Presentation (1 results)
