Impact of wind on mechanical wood properties of Pinus trees: a review
摘要
Wind represents a significant environmental factor impacting tree growth, driving adaptive growth strategies to maintain structural stability and functionality. While these physiological, anatomical, and morphological responses enhance tree survival, they often result in a decrease in mechanical wood properties. This review examines current state of knowledge surrounding the interactions between wind and Pinus species, with a particular focus on the resulting modifications in wood properties such as density, microfibril angle (MFA), and stiffness. Acute wind events, such as storms and hurricanes, can cause severe damage including stem breakage or uprooting, whereas chronic wind exposure induces adaptive growth responses. These responses are mediated through cambial activity, which transduces and responds to mechanical stimuli to produce wood cells with distinct characteristics, including altered tracheid length, cell wall thickness, and MFA. Morphological adaptations to chronic wind exposure include shorter, more compact tree forms characterized by increased radial growth and enhanced taper. Such adaptations result in stems containing mixtures of normal, flexure, and compression wood, contributing to irregular stem geometry and exaggerated heterogeneity in properties. Compression and flexure wood exhibit distinct mechanical and anatomical properties, including higher density and MFA, which collectively reduce stiffness. Despite extensive research on compression wood, flexure wood remains underexplored, and comparative studies on wind-induced wood properties across high- and low-wind environments within the same species are limited. Additionally, most investigations rely on artificially manipulated wind conditions, leaving a gap in understanding tree responses to natural wind environments. Addressing this knowledge gap is critical for advancing forest management practices and optimizing wood utilization. This study underscores the need to consider wind exposure in assigning end uses for timber and highlights the importance of integrating environmental factors into forestry research and management strategies.