Two separate periods of the LAI-VIs relationships using in situ measurements in a deciduous broadleaf forest

► NDVIHSSR and EVIHSSR capture the seasonal variations of LAI, but prematurely estimate the onset of the growing season because of the effect of the forest floor on the remote sensing images. ► The relationships between NDVIHSSR and EVIHSSR and in situ LAI were both better characterized as linear than non-linear for the one-period relationship. ► The two-period relationships better represented the seasonality of in situ LAI and in situ VI, and thus result in more accurate LAI estimations than the one-period relationship. ► EVI produced a better estimate of LAI than NDVI, especially in the leaf-expansion to -saturation period.