Spatial analysis of tree regeneration in a preserved area in Zagros forests, Iran

Abstract

Forest ecosystems are complex dynamical systems described by attributes of composition, structure, and function. To understand and manage forest ecosystems, we are required to explain and classify their dynamic structure and spatial patterns. We investigated the spatial patterns of trees and their regenerations in a preserved area in Zagros forests of western Iran. We applied geostatistical methods to examine the spatial pattern in distribution of tree and regeneration density and diversity. Fractal analysis was also used to characterize the complexity of the spatial patterns. The results showed that the mean of tree density per plot was 10.56 (S.E. ± 0.29) individual with canopy cover being 18.1 (S.E. ± 0.96) percent per plot. The mean of regeneration density was 3.06 (S.E. ± 0.23) individual in plot. We revealed spatially structured characteristics for tree density and diversity indices through the variograms that showed the presence of spatial autocorrelation. We also found that preservation favored density and diversity of tree regeneration in this area compared to unpreserved area. We also found that fractal dimension representing the unpredictability of spatial patterns, is high for trees and regeneration. This implies that although spatial dependence in semivariograms exists, it is generally fairly weak. These results revealed the scattered and homogeneous spatial distribution of trees and their regeneration in Zagros forests. It seems that the preservation action is not yet sufficient to effect on the spatial pattern of regeneration in this area. Therefore, conservation efforts must continue to complete the recovery of regenerated forest and flourishing of their spatial structure.

Keywords

• spatial ecology
• fractal dimension
• restoration
• semivariogram