Measuring Leaf Angle Distribution Using Terrestrial Laser Scanning in a European Beech Forest

Leaf angle distribution (LAD) is an important canopy structure metric. It controls the flux of radiation, carbon and water, and has therefore been used in many radiative transfer, meteorological and hydrological models. However, LAD is too tedious to measure using conventional manual methods. Terrestrial laser scanning (TLS) has recently been proposed to estimate LAD due to its ability to record unprecedented detailed plant 3D structure. However, previous research was restricted to a controlled environment with simple canopy structure. In this research, TLS was used in a natural deciduous European beech forest to estimate LAD. Digital hemispherical photograph (DHP) was also used as a reference. The results demonstrated that both TLS and DHP could capture a variation of LAD in beech plots at different succession stages. Compared to DHP, TLS has the advantage of resolving foliar and woody materials, as well as deriving the 3D distribution of leaf angles.