Wood anatomical traits associated with the mechanical behavior of tree species in agroforestry systems

Abstract Agroforestry systems have attracted increasing interest as a sustainable alternative for timber production by integrating commercial and native tree species. However, the relationships between wood anatomy and the mechanical performance of species cultivated under these systems remain poorly understood, particularly for native species. This study investigated the relationship between wood anatomical characteristics and the mechanical properties of Parapiptadenia rigida, Peltophorum dubium, Schizolobium parahyba e Eucalyptus grandis × Eucalyptus urophylla cultivated under the same agroforestry conditions in southern Brazil. Twelve 9-year-old trees were evaluated. Wood anatomy, basic density, and mechanical properties were determined from samples collected at breast height, and the relationships among variables were assessed using Pearson’s correlation and principal component analyses. Significant differences were observed among species for all anatomical and mechanical characteristics. P. rigida exhibited the highest basic density (0.652 g cm⁻ 3 ), the highest ray frequency (64.8 rays mm⁻ 2 ), and the greatest mechanical performance, whereas S. parahyba showed the largest vessel diameter (187.1 μm), the lowest basic density (0.277 g cm⁻ 3 ), and the lowest mechanical strength. P. dubium and E. grandis × E. urophylla exhibited intermediate performance. Basic density, fiber cell wall fraction, and ray frequency were positively correlated with all mechanical properties, whereas vessel, fiber, and ray dimensions were negatively correlated. Multivariate analyses showed that these anatomical attributes clearly discriminated the species and explained their different mechanical performances. The results confirm that wood mechanical performance results from the interaction between anatomical organization and basic density, demonstrating that cultivation in an agroforestry system preserves the technological potential of the evaluated species while expanding the technological knowledge of native timber species for sustainable production of higher value-added wood.