Models of the fine-scale spatial distributions of trees in managed and unmanaged forest patches with Abies alba Mill. and Fagus sylvatica L.

Abstract

Fine-scale spatial point-pattern analysis can give insights into the underlying pattern-creating biological processes in an environmental context. However, there are few studies comparing the spatial distribution of trees in managed stands and unmanaged forests that take into account their developmental stage. The main aim of this study was to assess and model the spatial patterns of Abies alba Mill. and Fagus sylvatica L. trees in managed and unmanaged forest patches in the early developmental stage.This study investigated tree communities dominated by A. alba and F. sylvatica in the Świętokrzyskie Mountains in Central Europe. From 2016 to 2018, 60 sample plots representing the growing-up developmental stage were randomly selected: 30 from managed stands and 30 from unmanaged forests. Models of the fine-scale spatial distributions of the trees were distinguished using hierarchical cluster analysis (HCA), analysis of group similarities (ANOSIM), and multiple response permutation procedures (MRPP). Indices based on the K-function and the O-ring statistic, ILr and IOr, respectively, were developed and used as clustering variables. The proposed indices assume values from −1 to 1 for random patterns; values > 1 indicate aggregation, and values < −1 indicate regularity.Models of the fine-scale spatial distributions of the trees differed only slightly between the managed and unmanaged patches. These models suggest that in the investigated sample plots, the fine-scale spatial patterns (with distances among the trees not exceeding 10 m) were usually random. Only in a few patches were the tree distributions found to be aggregated, from 5 to 10 m and from 7 to 10 m in the managed stands and the unmanaged forests, respectively. The relatively similar models of the fine-scale spatial distributions of the trees in the managed and unmanaged forest patches in the growing-up developmental stage show that early successional forest dynamics follow a parallel trajectory of recovery. The long-term application of the shelterwood system as well as self-regeneration and self-regulation natural processes led to the creation of the similar spatial structures of the trees. This observation may be helpful in the design of planting patterns and/or harvesting schedules.