Estimation of diurnal hydraulic status of spruce trees using drone-based hyperspectral images and green shoulder indices

The "two water-worlds hypothesis" has attracted significant public attention because it is an accessible way to describe the partitioning of water sources within catchments. This manuscript adds a new degree of complexity to that idea by recognizing that co-occurring tree species, which root at different depths, also use different water sources. So it leads to at least three water worlds.