Evaluating tree-ring proxies for representing the ecosystem productivity in India

Area of Science:

• Ecology
• Climate Science
• Forestry

Background:

• Terrestrial ecosystems, particularly forests, are vital carbon sinks, mitigating climate change by absorbing atmospheric CO2.
• Forest carbon sequestration is largely stored in woody biomass, with studies often using eddy covariance (EC) and remote sensing for analysis.
• Long-term ecosystem carbon flux data is limited, hindering the study of historical carbon sequestration using proxies like tree rings.

Purpose of the Study:

• To investigate the long-term linkage between ecosystem-atmosphere carbon exchange and tree-ring growth.
• To compare simulated gross primary productivity (GPP) with tree-ring indices over a 140-year period.
• To assess species-specific correlations in the northwestern Himalayan region.

Main Methods:

• Utilized Coupled Climate Carbon Cycle Model Intercomparison Project (C4MIP) model outputs for simulated gross primary productivity (GPP).
• Compared 140-year GPP records with tree-ring growth indices (RWI) from three coniferous species in the northwestern Himalayas.
• Analyzed the correlation strength between GPP and RWI for Pinus roxburghii, Picea smithiana, and Cedrus deodara.

Main Results:

• Established a long-term linkage between simulated ecosystem GPP and tree-ring growth indices.
• Found that the correlation between GPP and RWI varied significantly among the studied coniferous tree species.
• Highlighted the potential of tree-ring indices as proxies for historical ecosystem productivity.

Conclusions:

• Tree-ring indices offer a valuable proxy for reconstructing long-term ecosystem productivity and carbon sequestration.
• Species-specific responses underscore the complexity of forest carbon dynamics in response to climate drivers.
• This research provides a foundation for improved climate change impact assessments in forest ecosystems.