A new method for characterizing point patterns in plant ecology

This paper describes new methods for the detection of the characteristics of spatial point patterns. based on counting plants in the circumcircles of triangles defined by triplets of the points themselves. In addition to counting points in the circumcircle, a further refinement is to count also the points in a ring around the circumcircle of the same area. This approach can be applied in a univariate form, with one species or one kind of plant, to detect and evaluate the best-defined patches of plants and gaps. In the bivariate form. the method can be used to investigate the spatial characteristics of the relationship between different kinds of plants. These methods are illustrated by application to several data sets. In particular, the method is shown to be useful in describing the spatial relationship between seedlings and trees, both when the seedlings are on the forest floor beneath the canopy trees and when the seedlings represent post-fire regeneration.