Do Common Silvicultural Treatments Affect Wood Density of Mediterranean Montane Pines?

Daniel Moreno-Fernández,Andrea Hevia,Juan Majada,Isabel Cañellas

doi:10.3390/f9020080

Daniel Moreno-Fernández, Andrea Hevia + Show 2 more

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https://doi.org/10.3390/f9020080

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Abstract

Wood density is one of the most important and well documented wood quality attributes. However, studies focusing on the effects of thinning combined with pruning on wood density in Mediterranean areas are scarce, even though both are recommended practices in forests managed for the production of high-quality timber. We assess the effects of both silvicultural interventions on wood density traits (tree-ring, earlywood, and latewood) and on the percentage of latewood, on an annual scale, for the main timber species Pinus sylvestris L. and Pinus nigra Arnold (subsp. nigra and subsp. salzmannii) in Mediterranean mountains. To this end, three trials (one species per trial) were established in monospecific reforestations in the 1990s. Three silvicultural treatments were applied: thinning, thinning combined with pruning, and a control. At the time of installation, stand ages ranged from 26 to 37 years. Small differences were found among treatments in regard to the wood density attributes, with no significant effects of thinning and pruning on the studied wood traits in either timber species. The two subspecies of P. nigra presented comparatively denser wood than P. sylvestris. Our results suggest that thinning and pruning treatments can be applied without causing unfavourable changes to wood density.

Highlights

High quality wood products are usually obtained from large-size, knot-free stems [1]
We evaluate the effects of silvicultural treatments on the wood density of P. sylvestris and two subspecies of P. nigra in Mediterranean mountain areas
These average values were higher for P. nigra than for P. sylvestris

Summary

Introduction

High quality wood products are usually obtained from large-size, knot-free stems [1]. Appropriate forest management is essential to obtaining high-value products from timber species [2]. This will involve thinning operations to reduce competition [3,4], thereby promoting increased growth rates and larger diameters, while knots and branch-related defects can be restricted to a central knotty core through pruning operations [2,5,6]. Wood density is assumed to be one of the most important wood quality attributes, since it influences mechanical properties such as wood strength, flexibility, and stiffness. It affects physiological wood construction costs, carbon storage [8,9,10], and the quality of paper products and by-products [11,12]

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