The degree of aggregation or clumping of leaves was often considered to have a significant effect on transmission of light by a plant canopy. We produced simulated distributions of leaves, represented by small circles, with degrees of aggregation varying from random to a strongly clumped distribution. We calculated the interception of every leaf using different lines to represent light beams, pointing from the origin to different directions: every 5{\textdegree} in azimuth and elevation. The percentage of lines not intercepting any leaf was considered as the transmittance of light. The simulations considered two factors: leaf area index (LAI) (from 1 to 9) and degree of aggregation (from random to 100\%). The results for a random distribution fit the predictions of the negative exponential function. A degree of clumping of 20\% produced significant differences with respect to the predictions of the negative exponential function. The relationship between relative variance (rv) of the leaves{\textquoteright} distribution and degree of clustering is largely independent of LAI for values ranging from 3 to 7. We suggest that result could be used as a method to estimate the degree of clumping of real canopies, through the analysis of hemispherical images.

}, keywords = {Cluster, Leaf area index, model, Transmittance}, author = {de Castro, F. and Fetcher, N.} }