Variation of Clumping Index With Zenith Angle for Forest Canopies

Canopy clumping index (CI) characterizes the extent of the nonrandom spatial distribution of foliage elements within a canopy and is critical for determining the radiative transfer, photosynthesis, and transpiration processes in the canopy. It is widely perceived that the CI increases with zenith angle ($\theta$ ), because between-crown gaps decrease in size and number with increasing $\theta $ . In this study, we demonstrate that this is not …