## 3 Results
### Relationships Between SIF and Tr  
SIF and Tr exhibited significant linear relationships, with stronger correlation coefficients at daily scale than half-hour scale (Table 1, Figure 4). The total order of linear regression slopes (k) was poplar > Chinese cork oak > abrovitae, which suggests that poplar has a higher transpiration rate at the same level of fluorescence intensity. The differences in temporal scales did not affect k of Chinese cork oak and poplar. For abrovitae, k on the daily scale was slightly higher than on the half-hourly scale. Weather also affected the relationship between SIF and Tr. For Chinese cork oak, k, correlation coefficient, and R\({}^{2}\) were greater on cloudy days compared to sunny days. In contrast, the relationship for poplar was stronger on sunny days. The diurnal observation time affected the correlation between SIF and Tr, altering the slope of the zero-intercept linear regression (Tr/SIF). In general, the SIF-Tr relationship exhibited a midday decrease (Figure 5). Under different weather conditions, the Tr/SIF in three plantations generally showed an increasing trend throughout the day. However, the Tr/SIF in Chinese cork oak and poplar exhibited a midday decrease on cloudy days. Figure 3: Diurnal dynamics of SIF (red line) and Tr (blue line) in Chinese cork oak (total, (**a**); sunny, (**b**); cloudy, (**c**)), poplar (total, (**d**); sunny, (**e**); cloudy, (**f**)), and abrovitae (total, (**g**); sunny, (**h**); cloudy, (**i**)) plantations under different weather conditions. Dots and shaded areas represent mean values and standard deviations, respectively, calculated from half-hour data collected at the same time across all observed days. \begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline \multirow{2}{*}{
\begin{tabular}{c} **Temporal** \\ **Scale** \\ \end{tabular} } & \multirow{2}{*}{**Species**} & \multicolumn{3}{c}{**Total**} & \multicolumn{3}{c}{**Sunny**} & \multicolumn{3}{c}{**Cloudy**} \\ \cline{3-10}  & & **Pearson** & \multirow{2}{*}{**R2**} & \multirow{2}{*}{**k**} & \multicolumn{2}{c}{**Pearson**} & \multirow{2}{*}{**R2**} & \multirow{2}{*}{**k**} & \multicolumn{2}{c}{**Pearson**} & \multirow{2}{*}{**R2**} & \multirow{2}{*}{**k**} \\  & & **Coefficient** & & & & & & & & **Coefficient** & \\ \hline \multirow{4}{*}{half-hour} & Chinese & \multirow{2}{*}{0.597 **} & \multirow{2}{*}{0.356} & \multirow{2}{*}{0.326} & \multirow{2}{*}{0.551 **} & \multirow{2}{*}{**+**} & \multirow{2}{*}{0.303} & \multirow{2}{*}{0.306} & \multirow{2}{*}{0.650 **} & \multirow{2}{*}{0.422} & \multirow{2}{*}{0.395} \\  & cork oak & & & & & & & & & \\ \cline{2-10}  & poplar & 0.641 ** & 0.411 & 0.636 & 0.673 ** & 0.453 & 0.715 & 0.629 ** & 0.395 & 0.595 \\ \cline{2-10}  & arborvitae & 0.605 ** & 0.366 & 0.208 & 0.603 ** & 0.364 & 0.223 & 0.615 ** & 0.378 & 0.216 \\ \hline \multirow{4}{*}{daily} & Chinese & \multirow{2}{*}{0.746 **} & \multirow{2}{*}{0.557} & \multirow{2}{*}{0.338} & \multirow{2}{*}{0.644 **} & \multirow{2}{*}{0.415} & \multirow{2}{*}{0.325} & \multirow{2}{*}{0.793 **} & \multirow{2}{*}{0.628} & \multirow{2}{*}{0.400} \\  & cork oak & & & & & & & & & \\ \cline{2-10}  & poplar & 0.737 ** & 0.543 & 0.624 & 0.778 ** & 0.605 & 0.665 & 0.724 ** & 0.524 & 0.593 \\ \cline{2-10}  & arborvitae & 0.640 ** & 0.409 & 0.249 & 0.683 ** & 0.466 & 0.354 & 0.669 ** & 0.447 & 0.308 \\ \hline \hline \end{tabular}  
* indicates a highly significant correlation (\(p<\) 0.01).  
\end{table} 
Table 1: Pearson correlation coefficients, linear regression determination coefficients (R2), and slopes between SIF and Tr at half-hour and daily scales in three plantations. Figure 4: Relationships between SIF and Tr in Chinese cork oak (total, **(a)**; sunny, **(b)**; cloudy, **(c)**), poplar (total, **(d)**; sunny, **(e)**; cloudy, **(f)**), and arborvitae (total, **(g)**; sunny, **(h)**; cloudy, **(i)**) plantations under different weather conditions. Dots and lines represent value and linear regressions, respectively.