## 4 Methods
### PAR and APAR  
The photosynthetically active radiation (PAR) is defined as the domain of incoming solar radiation exploited by green vegetation for photosynthesis (400 - 700 nm). PAR can be derived from a budget modelling approach, with the potential solar radiation calculated from the geographical location [45, 22], or modelled from remote sensing data [18, 19]. In this study, PAR was obtained on pixel-by-pixel basis from the budget modelling approach, which computes the solar irradiance at the \begin{table}
\begin{tabular}{|p{56.9 pt}|p{56.9 pt}|p{56.9 pt}|p{56.9 pt}|p{56.9 pt}|p{56.9 pt}|} \hline
**Parameter** & **Units** & **Description** & **Land cover class** & **Source** \\ \hline \multirow{2}{*}{\(LUE_{opt}\)} & \multirow{2}{*}{gC/MJ} & Optimum radiation conversion efficiency & \multirow{2}{*}{0.61} & \multirow{2}{*}{0.97} & \multirow{2}{*}{This study} \\ \cline{1-1} \cline{5-6} \(Q_{10}\) & & & & & \\ \cline{1-1} \cline{5-6} \(T_{b}\) & \({}^{\circ}\)C & Base temperature & 20.0 & 20.0 & [PERSON] _et al._[37] \\ \hline SLA & m\({}^{2}\)/kg C & Specific leaf area & 40.0 & 40.0 & [PERSON] _et al._[37] \\ \hline \multirow{2}{*}{\(r_{m,root}\)} & \multirow{2}{*}{gC/gC/day} & Maintenance respiration coefficient for fine roots at 20\({}^{\circ}\)C & \multirow{2}{*}{0.005} & \multirow{2}{*}{0.006} & \multirow{2}{*}{[PERSON] _et al._[37]} \\ \cline{1-1} \cline{5-6} \(r_{m,leaf}\) & \multirow{2}{*}{gC/gC/day} & Maintenance respiration coefficient for above-ground plant parts at 20\({}^{\circ}\)C & \multirow{2}{*}{0.009} & \multirow{2}{*}{0.01} & \multirow{2}{*}{[PERSON] _et al._[37]} \\ \hline \multirow{2}{*}{\(r_{g,root}\)} & \multirow{2}{*}{gC/gC} & Growth respiration coefficient for fine roots & \multirow{2}{*}{0.3} & \multirow{2}{*}{0.3} & \multirow{2}{*}{[PERSON] _et al._[37]} \\ \cline{1-1} \cline{5-6} \(r_{g,leaf}\) & \multirow{2}{*}{gC/gC} & Growth respiration coefficient for above-ground plant parts & \multirow{2}{*}{0.3} & \multirow{2}{*}{0.3} & \multirow{2}{*}{[PERSON] _et al._[37]} \\ \cline{1-1} \cline{5-6} \(r_{a,root}\) & \multirow{2}{*}{none} & Carbon allocation fraction for fine roots & \multirow{2}{*}{1.0} & \multirow{2}{*}{1.0} & \multirow{2}{*}{[PERSON] _et al._[37]} \\ \cline{1-1} \cline{5-6} \(r_{a,leaf}\) & \multirow{2}{*}{none} & Carbon allocation fraction for above-ground plant parts & \multirow{2}{*}{1.0} & \multirow{2}{*}{1.0} & \multirow{2}{*}{[PERSON] _et al._[37]} \\ \cline{1-1} \cline{5-6} \(\mathrm{BGB}/AGB_{l}\) & \multirow{2}{*}{none} & Ratio of below ground biomass to above ground biomass & \multirow{2}{*}{0.63} & \multirow{2}{*}{1.08} & \multirow{2}{*}{This study} \\ \hline \multirow{2}{*}{\(VPD_{step}\)} & \multirow{2}{*}{Pa} & \multirow{2}{*}{\begin{tabular}{} \end{tabular} } & \multirow{2}{*}{5000} & \multirow{2}{*}{4100} & \multirow{2}{*}{[PERSON] _et al._[37]} \\ \cline{1-1} \cline{5-6} \(VPD_{start}\) & & & & & \\ \cline{1-1} \cline{5-6} \(VPD_{start}\) & \multirow{2}{*}{Pa} & \multirow{2}{*}{\
\begin{tabular}{} \end{tabular} } & \multirow{2}{*}{1000} & \multirow{2}{*}{970} & \multirow{2}{*}{[PERSON] _et al._[37]} \\ \cline{1-1} \cline{5-6} \(T_{opt}\) & \({}^{\circ}\)C &
\begin{tabular}{} \end{tabular} & \multirow{2}{*}{25.0} & \multirow{2}{*}{25.0} & \multirow{2}{*}{[PERSON] _et al._[37]} \\ \cline{1-1} \cline{5-6} \(T_{range}\) & \({}^{\circ}\)C & Maximum temperature range & 40.0 & 40.0 & [PERSON] _et al._[37] \\ \hline F & gC/m\({}^{2}\)/day & Soil respiration rate at 0\({}^{\circ}\)C & \multirow{2}{*}{1.250} & \multirow{2}{*}{1.480} & [PERSON] _et al._[55]; [PERSON] \& [PERSON], \\ \cline{1-1} \cline{5-6}  & & & & & [62] \\ \hline \end{tabular}
\end{table} 
Table 2: The constant parameters, their descriptions, and values used for the light use efficiency model in this study. top of the atmosphere and transforms it to the amount of solar radiance coming to the Earth's surface.