Quantifying the Intrinsic Q₁₀ of Ecosystem and Component Respiration in a Eucalypt Forest: Implications for...

Ecosystem respiration is a major biosphere-atmosphere carbon flux that creates a positive feedback effect on global warming. However, our current poor understanding of the temperature sensitivity of respiration has led to uncertainties in estimating the strength of this feedback. In this study, a time-series decomposition technique incorporating wavelet coherence analysis was designed to assess the temperature sensitivity (Q₁₀) of ecosystem (R_eco), stem (R_stem), and soil (R_soil) respiration in a mature eucalypt forest, providing new insights into respiration-temperature response relationships. Our method effectively calculated intrinsic Q₁₀ values for R_eco, R_stem, and R_soil of 1.40 (95% CI: 1.34-1.46), 1.61 (95% CI: 1.54-1.67), and 1.57 (95% CI: 1.37-1.78), while the apparent Q₁₀ values were 1.92, 1.13, and 2.38, respectively. We found that the non-temperature confounding effect was the main factor leading to the discrepancy between the apparent Q₁₀ calculations and the intrinsic Q₁₀. Furthermore, by comparing our intrinsic Q₁₀ values with the conventional value of 2.0, adopted in many Earth system models, we found that past model simulation results may have overestimated the sensitivity of terrestrial carbon release to temperature increases. Our study establishes a refined methodological framework for determining accurate Q₁₀ values, thereby helping reduce uncertainties in modeling global climate-carbon cycle interactions.