Longitudinal Anatomical Variation of Wood in Stem and Branch of Six Forest Species from the Amazon Region and Its Relationship with Wood Specific Gravity

Wood functional traits provide information for the management and sustainable use of species. This study evaluated the wood specific gravity (SG) and nine anatomical characteristics of wood in six sections (three levels of stem height and three orders of the branch) in six species of bioeconomic importance for the Colombian Amazon region: Jacaranda copaia, Virola elongata, Virola peruviana, Cedrelinga cateniformis, Erisma uncinatum, and Cabari macrocarpa. The results showed that low- and medium-SG species have branches with equal or greater SG than the stem. In this group, Erisma uncinatum and Virola peruviana showed no differences between their sections. In contrast, for high-SG species such as Cabari macrocarpa, the relationship was inverse. Fiber thickness correlated mainly with SG, with no differences between sections, except in Cabari macrocarpa. Fiber length decreased in all species in the stem-to-branch direction. The other characteristics varied, suggesting an optimization in the effort of water transport along the tree. These findings infer a potential sustainable use of branches of tree species with low biomechanical variation, such as Erisma uncinatum and Virola peruviana. They also demonstrate the hydraulic and mechanical adaptability of these species, which is relevant when facing climate change scenarios.