The influence of drought and thinning on leaf area index estimates from canopy transmittance method

Abstract

Leaf area index (LAI) estimates from litterfall and from canopy transmittance measurements in photosynthetically active radiation (PAR) and total solar irradiance wave bands were compared in Turkey oak (Quercus cerris) stands. The aim was to evaluate advantages and limits of the transmittance measurements method in estimating LAI. Differences in stand density and LAI due to silvicultural operations led to significant differences in transmittance but did not affect light extinction coefficient (k). On the contrary, environmental constraints influenced canopy properties as transmittance and k. However, the variability in canopy properties do not limit the capability of canopy transmittance, measured in the PAR wave band, to be a good predictor (error < ±5%) of LAI at stand level.