FIGURE 7.

Seasonal differences in the drone‐based remotely sensed photochemical reflectance index (PRI), as a function of soil water potential (SWP), at the Pfynwald Pinus sylvestris experimental forest site for two growing seasons. Precipitation manipulation (irrigation) treatments are represented with different shades of gray: dark for control (C), light for irrigation‐stop (IS) and white for irrigated (I). (a) and (b) show PRI and SWP for C (solid black line), IS (dashed black line) and I (solid blue line) treatments, as a function of date for (a) 2019 and (b) 2020. (c) Shows (sub)plot‐level PRI measurements and predictions from the linear mixed‐effects model with SWP at 80 cm depth averaged over the preceding 5 days and its interaction with irrigation treatment as fixed effects and date and (sub)plots as random effects [Colour figure can be viewed at wileyonlinelibrary.com]