Structural Dynamics and Successional Trajectories in Zagros Mountain Oak Coppice Forests

Aims: Understanding the structural dynamics of unmanaged oak coppices is crucial, as many of the world’s forests remain unmanaged. While previous studies have focused on coppice dynamics in mesic woodlands, there needs to be a more significant gap in understanding these processes in semi-arid regions. The study aims to examine the structural modifications, successional trajectories, and floristic diversity within semi-arid oak coppices in the Zagros Mountains, utilizing a comprehensive dataset obtained from an extensive land survey. Materials & Methods: The study was conducted in a ۱۷۵ km strip of Zagros Mountain forests dominated by Quercus brant ii. Ninety-four even-aged stands from ۱۴ forests were selected. Structural attributes were evaluated, including tree density, basal area, canopy cover, and floristic diversity measures. A list of vascular flora was documented for each successional stage using the Raunkiær plant life-form classification. Data analysis involved polar ordination, clustering, and multivariate techniques.  Findings: Density, Holdridge complexity index, basal area, and cover were identified as the most influential variables. Two main trajectories, progressive and retrogressive, were identified, with eight successional stages. Significant differences in structural variables were observed across trajectories, with floristic diversity peaking in the middle stages. The later stages of the progressive trajectory showed a significant increase in the relative cover and basal area of Fraxinus rotundifolia. The study demonstrates the existence of a progressive successional trajectory in unmanaged coppice forests influenced by disturbances. Stand age, mean diameter of sprout clumps, and flora diversity do not solely determine the successional stages within this trajectory. Conclusion: While transforming Zagros Mountain oak coppice into high forests is unlikely, there is potential for redirecting succession toward more resilient and diverse ecosystems. We recommend management interventions beyond protection, promoting uneven-aged stands, increasing density and cover, and encouraging species like Fraxinus. These strategies can enhance ecological integrity and foster sustainable woodland ecosystems in the Zagros region.

کلیدواژه ها:

Woodland resilience ، Floristic diversity ، Vegetative regeneration ، Quercus brantii ، Semi-arid forests