How to improve forest biodiversity management by comparing broad-scale stands' structural spatial heterogeneity between two forests

Abstract

This article aims to propose a methodological approach to the determination of differences in structural spatial heterogeneity between two different forests, exhibiting differences in some characteristics. By comparing the variances of the Gini-Simpson index values calculated from diameter at breast height (DBH) or tree height distributions in randomly sampled plots, structural differences can be effectively quantified. An F-test is employed to compare these variances, and while we use the Gini-Simpson index as an example, our method is flexible and can be applied using any chosen diversity index appropriate for the user's specific research context. A case study was conducted in Fagus sylvatica L. stands in the central Rhodope mountains, Greece, using plots from high productivity and medium productivity sites. The results showed significantly greater variance in Gini-Simpson index values in medium productivity sites compared to high productivity sites, indicating higher spatial diversity heterogeneity. This straightforward method requires only basic DBH or tree height data, making it practical for integration into forest stand structure studies and aiding in informed forest management decisions. The approach provides a statistically sound and flexible tool for comparing structural spatial heterogeneity across different forests, potentially guiding practices aimed at enhancing stand complexity and ecological resilience