Leaf area indices of forest canopies from optical measurements.

摘要

Ground-based estimates of leaf area indices (LAI) of forest canopies and understorey vegetation in Jarvselja, Estonia were derived from measurements by the plant canopy analyzers LAI-2000 and hemispherical photographs as well as via allometric relations from traditional forest inventory variables from a forestry database. Regressions of LAI with the SPOT and Landsat satellite image-derived reflectance factors and combined indices were established. The LAI values correlated the best with the reduced simple ratio index defined by the red, near and middle infrared bands. The standard error of the estimate of all regressions between the LAI and satellite image-based variables is about 1.5 units or higher.