## Materials and Methods
### Flux-based Ecosystem Model and Parameters
#### 2.1.1 Leaf-level photosynthesis  
Leaf-level photosynthesis (A) is based on the model developed by [PERSON] [43]. For C3 plants, gross leaf CO\({}_{2}\) uptake (A, \(\mu\) mol CO\({}_{2}\) m\({}^{-2}\) s\({}^{-1}\)) is calculated as follows:  
\[A=\min\{J_{c},J_{e}\} \tag{1}\] \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Parameter**} & \multirow{2}{*}{**Definition**} & \multirow{2}{*}{**Unit**} & \multirow{2}{*}{**Value**} & \multicolumn{3}{c}{**Range**} & \multirow{2}{*}{**Reference**} \\ \cline{3-3} \cline{5-8}  & & & & **Minimum** & & **Maximum** \\ \hline \multirow{2}{*}{\(\alpha_{q}\)} & \multicolumn{2}{c}{Canopy quantum efficiency of photon conversion} & mol mol\({}^{-1}\) photon & 0.28 & 0 & 0.5 & [40] \\ \hline \multirow{2}{*}{\(K_{e}^{25}\)} & Michaelis-Menten constant for carboxylation & \(\mu\) mol mol\({}^{-1}\) & 460 & 50 & 600 & [40] \\ \hline \multirow{2}{*}{\(E_{K_{c}}\)} & Activation energy of K\({}^{25}\) & Jmol\({}^{-1}\) & 59,356 & 30,000 & 150,000 & [40] \\ \hline \multirow{2}{*}{\(E_{K_{o}}\)} & Activation energy of K\({}^{25}_{o}\) & Jmol\({}^{-1}\) & 35,948 & 10,000 & 60,000 & [40] \\ \hline \multirow{2}{*}{\(K_{o}^{25}\)} & Michaelis-Menten constant for oxygenation & mol mol\({}^{-1}\) & 0.33 & 0.2 & 0.5 & [40] \\ \hline \multirow{2}{*}{\(E_{Vm}\)} & Activation energy of V\({}^{25}_{m}\) & Jmol\({}^{-1}\) & 58,520 & 10,000 & 100,000 & [40] \\ \hline \multirow{2}{*}{\(\Gamma_{e}^{25}\)} & CO\({}_{2}\) compensation point without dark respiration & \(\mu\) mol mol\({}^{-1}\) & 42.5 & 10 & 200 & [40] \\ \hline \multirow{2}{*}{\(\tau_{J_{m_{m_{n}}}}\)} & Ratio of J\({}_{m}\) to V\({}^{25}_{m}\) at 25 \({}^{\circ}\)C & - & 1.79 & 1 & 5 & [40] \\ \hline \multirow{2}{*}{\(ER_{0}\)} & Whole ecosystem respiration at 0 \({}^{\circ}\)C & \(\mu\) mol CO\({}_{2}\) m\({}^{-2}\) s\({}^{-1}\) & 2.5 & 1 & 5 & [41] \\ \hline \multirow{2}{*}{\(Q_{10}\)} & Temperature dependency of ecosystem respiration & - & 2 & 1 & 3 & [41] \\ \hline \multirow{2}{*}{\(\
u_{m}^{25}\)} & Maximum carboxylation rate at 25 \({}^{\circ}\)C & \(\mu\) mol CO\({}_{2}\) m\({}^{-2}\) s\({}^{-1}\) & 29 & 10 & 300 & [40] \\ \hline \multirow{2}{*}{\(f_{Ci}\)} & Ratio of internal CO\({}_{2}\) to air CO\({}_{2}\) & - & 0.87 & 0.5 & 0.9 & [40] \\ \hline \multirow{2}{*}{\(K_{n}\)} & Canopy extinction coefficient for light & - & 0.8 & 0.7 & 0.9 & [40] \\ \hline \multirow{2}{*}{\(E_{\tau_{n}^{\rm as}}\)} & Activation energy of CO\({}_{2}\) compensation point at 25 \({}^{\circ}\)C & J mol\({}^{-1}\) & 60,000 & 30,000 & 100,000 & [40] \\ \hline \multirow{2}{*}{\(g_{I}\)} & Empirical coefficient in Leuning model & - & 1657 & 100 & 2000 & [42] \\ \hline \multirow{2}{*}{\(D_{0}\)} & Empirical coefficient in Leuning model & kPa & 2.74 & 1 & 10 & [42] \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Symbols, definitions, units, initial values, ranges and sources of 16 parameters of the Flux-based ecosystem model (FBEM) used in a sensitivity analysis. where \(J_{e}\) and \(J_{C}\) represent light electron transport (\(\mu\) mol CO\({}_{2}\) m\({}^{-2}\) s\({}^{-1}\)) and the rates limited by carboxylation enzymes (\(\mu\) mol CO\({}_{2}\) m\({}^{-2}\) s\({}^{-1}\)), respectively.