Wood anatomical variation in Andean alder (Alnus acuminata) from the northern Peruvian Andes: Implications for utilization

Summary Alnus acuminata , also known as Andean alder, is a fast-growing tree native to the Andean regions of South America. Although it is used in agroforestry systems, for soil erosion control, and in rural construction, its wood is underutilized compared to that of other planted species. This study examines the radial and between-tree variation in wood anatomical traits of A. acuminata , aiming to understand their influence on the potential use of the wood in value-added applications. Nine trees were sampled from three sites in the Cajamarca region, northern Peru, with wood cores extracted along the pith-to-bark direction. Histological analyses were conducted to assess fiber, vessel, and ray traits at four radial positions. The results showed significant radial variation in fiber length and wall thickness, and in vessel diameter, area, frequency, and percentage, with values increasing from the area near the pith toward the outer wood. Inner wood exhibited shorter and thinner fibers, while outer wood had longer and thicker fibers, enhancing mechanical stability and wood density. In contrast, the size of the rays did not vary significantly across radial positions. These patterns are crucial for distinguishing juvenile wood and mature wood, which have important implications for wood processing and the development of value-added products. The pronounced radial patterns and high between-tree variability indicate a high level of wood heterogeneity of A. acuminata trees, emphasizing the need for well-managed plantations to ensure wood quality and uniformity. This study advances the understanding of Andean alder wood properties and sets the stage for future research on its sustainable use in the Andean region.