## 3 Results
### Annual C-fluxes Under Current and Future Climate Conditions  
Across the post-fire chronosequence plots, the effect of stand structure, as regulated by the time since the last fire event, on GPP and NPP was similar across all climate scenarios. In particular, GPP seemed to increase with stand age and LAI from ca 445 to 880 g C m\({}^{-2}\) year\({}^{-1}\), and then to decline in the mature (92 years old) plot to ca 830 (g C m\({}^{-2}\) year\({}^{-1}\)) under baseline climate conditions (Figure 7a). NPP followed a similar pattern to GPP, ranging from ca 300 to 530 g C m\({}^{-2}\) year\({}^{-1}\), with the mature stand reaching 505 g C m\({}^{-2}\) year\({}^{-1}\). This GPP vs. age trajectory remained consistent under both climate change scenarios and reference periods. Across all post-fire plots, simulated GPP was 7.7-13.8% and 8.8-28.8% lower than the baseline GPP under the RCP4.5 and RCP8.5 scenarios, respectively (Table 3). Figure 4: Estimated (**a**) GPP (Gross Primary Productivity), (**b**) \(\mathrm{R}_{\mathrm{het}}\) (soil heterotrophic respiration) and (**c**) NEP (Net Ecosystem Productivity) per elevation, and setup for elevation gradient plots. Setup conLAIvarT was with constant value for LAI (1.96) and variant temperature according to local lapse rate; varLAIconT was with variant LAI, according to our measurements, and constant temperature; and varLAIvarT was with variant LAI and temperature. Error bars are \(\pm\) standard deviation. Figure 5: Simulated mean daily values of GPP (Gross Primary Productivity) as green line, R\({}_{\text{het}}\) (soil heterotrophic respiration) as red line and NEP (Net Ecosystem Productivity) as black line for plots along the post-fire chronosequence gradient according to the day of the year (Doy). Figure 6: Simulated mean daily values of GPP (Gross Primary Productivity) as green line, R\({}_{\text{het}}\) (soil heterotrophic respiration) as red line and NEP (Net Ecosystem Productivity) as black line for plots along the elevation gradient according to the day of the year (Doy). A similar pattern was observed for R\({}_{\rm het}\) which also increased with stand age, from ca 170 to 400 g C m\({}^{-2}\) year\({}^{-1}\) before declining in the mature stand at ca 320 g C m\({}^{-2}\) year\({}^{-1}\) under baseline climate conditions (Figure 7b). Across the two climate change scenarios, R\({}_{\rm het}\) exhibited a greater percentage difference from baseline conditions, compared to GPP (Table 3). Notably, under the RCP8.5 scenario in the last period, R\({}_{\rm het}\) was higher than in all other scenarios and periods. In the post-fire chronosequence plots, NEP followed a different pattern. NEP was simulated to peak at the mature stand (92 years old), varying from ca 130 to 190 g C m\({}^{-2}\) year\({}^{-1}\) from the younger to the older plot, respectively, under baseline climate conditions (Figure 7c). Across all post-fire plots, the mean NEP under the different climate change scenarios ranged from 46.1 to 148% of baseline conditions (Table 3), with the RCP8.5 scenario during the last period showing the lowest values compared to all other simulations. The annual GPP of plots found across the elevation gradient ranged from ca 605 to 1070 g C m\({}^{-2}\) year\({}^{-1}\) under baseline conditions (Figure 8a) and decreased with the severity of the climate change scenario (Table 3). At the same time, NPP was estimated to range from ca 390 to 630 g C m\({}^{-2}\) year\({}^{-1}\). Under baseline conditions, R\({}_{\rm het}\) ranged from ca 170 to \begin{table}
\begin{tabular}{l c c c c} \hline \hline  & **RCP4.5 2060** & **RCP4.5 2100** & **RCP8.5 2060** & **RCP8.5 2100** \\ \hline GPP (\% change) & \(-13.2\) & \(-7.7\) & \(-8.8\) & \(-28.8\) \\ R\({}_{\rm het}\) (\% change) & 10.7 & 12.9 & 15.5 & 36.2 \\ NEP (\% change) & \(-56\) & \(-46.1\) & \(-54.2\) & \(-148\) \\ \hline \hline \end{tabular}
\end{table}