Figure captions
FIGURE 1: Environmental data in Rosinedal in 2012 and 2013. Sum of daily precipitation (A), daily mean photosynthetic photon flux density (B), daily mean temperature (C) and daily VPD during day light hours (D) in the fertilised (F, black circle) and in the reference (R, white circle) plots, respectively. Grey areas represent the thermal growing season.
FIGURE 2: Canopy conductance corrected by \(\hat{\alpha}\) for the fertilised (black circles and, solid lines) and the reference (white circles, dashed lines) plots in 2012 and 2013. Grey areas represent the thermal growing seasons
FIGURE 3: Atmospheric δ13Casignature in 2012 and 2013 (A) and phloem δ13Cp signature in 2012 (B) ± SE (n = 15). ns, +, *, **, *** correspond to p ≥ 0.1, p< 0.1, 0.05, 0.01 and 0.001, respectively, after pairwise comparison for each date. Grey areas represent the thermal growing seasons. The fertilised plot is represented in black circles and solid line and the reference plot in white circles and dotted line
FIGURE 4: Intrinsic water use efficiency at stand level (WUEi) for fertilised (filled circles and solid line) and reference plot (empty squares and dashed line) in 2012 and 2013, assuming a gm∞ assumption (green), a gm/\(g_{C\hat{\alpha}}\) = 2.67 assumption (yellow) or a gm = 0.31 mol CO2 m-2s-1 assumption (blue). Grey areas represent the thermal growing season Statistical results comparing WUEi between fertilised and reference plots: *** correspond to p < 0.001, respectively, after anova.
FIGURE 5: Daily GPPPRELES (orange) and GPPiso/SF (blue) in the fertilised plot (upper row) and in the reference plot (lower row). Shaded areas around the curves represent the Monte Carlo uncertainties. The shaded boxes represent the thermal growing seasons.
FIGURE 6: Annual sum of GPP for PRELES (2012 and 2013) and sap flux/isotopic (mean 2012 and 2013) method corrected by\(\ \hat{\alpha}\)considering the gm assumption, gm/\(g_{C\hat{\alpha}}\) = 2.67. Errors bars correspond to standard deviation and their values are in brackets and letters shows the statistical differences between the treatment combinations (α = 0.05).
FIGURE 7: Comparison of GPP on the fertilised plot vs the reference plot in 2012 (green) and 2013 (grey) with, GPPiso/SF for gm/\(g_{C\hat{\alpha}}\) = 2.67 assumption (A), and GPPPRELES (B). The black dashed line represents the 1:1 line.
FIGURE 8: Annual sum of GPP for sap flux/isotopic (mean 2012 and 2013) method corrected by\(\ \hat{\alpha}\) considering the gm assumptions, gm/\(g_{C\hat{\alpha}}\)= 2.67, gm = 0.31 mol CO2m-2 s-1 and infinite gm. Errors bars correspond to standard deviation and their values are in brackets and letters shows the statistical differences between the treatment combinations (α = 0.05).