Anatomical Predictors of Density and Hardness in Underutilized Amazonian Woods: A Basis for Substituting Commercial Timbers

Abstract The global timber market's reliance on a limited portfolio of Amazonian species creates supply chain volatility and sustainability challenges; however, market diversification is hindered by a lack of technical data on abundant, lesser-known woods. This study addresses this gap by providing a comprehensive technological characterization of 11 underutilized species from the Tapirapé-Aquiri National Forest, Brazil. We integrated wood anatomical measurements with assessments of density, dimensional stability, and dynamic hardness to evaluate structure-property relationships. Strong, positive correlations were established between key anatomical features (e.g., fiber wall thickness, ray density) and physical-mechanical traits like apparent density and hardness, validating their use as rapid predictors of wood performance. Principal component analysis (PCA) integrated these variables, successfully grouping the species into five distinct technological categories. These groups revealed clear differentiation in density and hardness profiles, defining their suitability for specific applications. Crucially, several groups demonstrate technological equivalence to overexploited commercial timbers. For example, Cenostigma tocantinum (Group 1) has a high density (0.85 g·cm −3 ) and hardness suitable for heavy construction, analogous to Hymenaea parvifolia , whereas Group 5 species are ideal for light carpentry. This provides a practical basis for substituting endangered species with mechanically compatible alternatives. By linking anatomy to performance, this study establishes a robust framework for diversifying the forest products industry, providing foundational data to introduce these species into supply chains, enhance industrial resilience, and support sustainable forest management.