Using codispersion analysis to quantify temporal changes in the spatial pattern of forest stand structure

Abstract

Forest development involves a complex set of ecological processes, such as dispersal and competition for light, which can generate a range of spatial patterns in forest structure that change through time. One interesting avenue of research in ecology is exploring whether spatial statistical methods can be brought to bear on such spatial patterns of forest structure to gain insight into the possible ecological processes that created them. In this study we applied a relatively new method to ecology, codispersion analysis, to investigate spatial covariation between two common measures of forest structure: tree abundance and mean basal area. We used data for four focal tree species from both a simulated and a real forest sampled at multiple time points. We assessed the significance of observed codispersion patterns using null models, in which tree diameters were iteratively and randomly reassigned to trees whose locations were kept constant. The results suggest that codispersion analysis could detect a range of spatial patterns in forest stand structure that were indicative of changing ecological processes.