Comparison of unmanaged and managed Trojan Fir–Scots pine forests for structural complexity

Ferhat Kara,John M Lhotka

doi:10.3906/tar-1903-58

Abstract

Unmanaged forests may exhibit a higher degree of biodiversity compared to managed forests. We examined and compared the stand structure, density, and volume of deadwood components of managed and unmanaged mixed forests of Trojan fir (Abies nordmanniana subsp. equi-trojani [Asch. & Sint. ex Boiss] Coode & Cullen)-Scots pine (Pinus sylvestris L.) in northern Turkey. The single-tree selection method has been employed in the managed forests. Density of large live trees ha-1, density of standing deadwood (SDW) ha-1, and volume of lying deadwood (LDW) (m3 ha-1) were calculated for both treatments (i.e. managed or unmanaged). Results showed that unmanaged forests had significantly higher density of large live trees and SDW compared to managed forests (P < 0.005). In addition, a lower amount of LDW was observed in the managed forests (P < 0.005). Our data suggest that the managed forests' lack of Scots pine trees in small- and middle-sized diameter classes indicates the potential risk of conversion of these mixed stands into pure Trojan fir forests. Initial results highlight the importance of large tree retention in managed stands to enhance biological diversity.

Highlights

Biological diversity influences the quality of life on Earth; its maintenance is one of the most critical tasks of forest management (Gauthier et al, 2018)
It has been suggested that unmanaged forests, compared to managed forests, may present better old-growth conditions with a higher degree of biodiversity including a greater number of large live trees as well as snags and lying deadwood [LDW]) (Bauhus et al, 2009)
We aimed to provide silvicultural recommendations for enhancing structural complexity and biological diversity in mixed Trojan fir–Scots pine forests of northern Turkey

Summary

Introduction

Biological diversity influences the quality of life on Earth; its maintenance is one of the most critical tasks of forest management (Gauthier et al, 2018). It has been suggested that unmanaged forests, compared to managed forests, may present better old-growth conditions with a higher degree of biodiversity including a greater number of large live trees as well as snags (i.e. standing deadwood [SDW]) and lying deadwood [LDW]) (Bauhus et al, 2009). Researchers have indicated that biological diversity can be maintained in managed forests if the forests are considered to be complex biological systems in a consistently changing environment (Kerr, 1999; Ciancio and Nocentini, 2011). Such research has been limited for many forest types

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