Key points are not available for this paper at this time.
A technique is described for estimating a foilage profile in a forest by a combination of measurements over random lines of points: (1) counts of leaf contacts on a plumb line below a tripod, (2) sightings on the heights of lowest leaves over grids of points, and (3) the proportions of sky unobscured by leaves.
MacArthur et al. (1969) studied this question.