Shrub willow canopy chlorophyll content estimation from unmanned aerial systems (UAS) data: Estimation and uncertainty analysis across time, space, and scales

•We predicted shrub willow CCC across time, space, and scales from UAS data.•Nested ANOVA method was able to evaluate spatial heterogeneity within pixels.•Models were based on NDVIre-based frequentist and Bayesian regression.•We compared and quantified model uncertainty using CI, CrI, and predictive RMSE.•A new perspective on model uncertainty is able to guide experimental design.