The leaf angle distribution (or LAD) of a plant canopy refers to the mathematical description of the angular orientation of the leaves in the vegetation.
This may be interpreted as a strategy by that plant species to maximize exposure to light, an important constraint to growth and development.
The LAD of a plant canopy has a significant impact on the reflectance, transmittance and absorption of solar light in the vegetation layer, and thus also on its growth and development.
Accurately measuring the statistical properties of leaf angle distributions is not a trivial matter, especially for small leaves.
This may be done, for instance, with a Spatial Coordinate Apparatus, which is an articulated mechanical device capable or recording the position in three-dimensional space of three separate points forming a small triangle.