Traits and trade-offs of wood anatomy between trunks and branches in tropical dry forest species

Key message Differences in wood traits are related to contrasting forces acting over trunks and branches. The wood economic spectrum is one of the most important groups of traits for plant performance due to the multiple functions in mechanical support, water conductivity and water and nutrient storage. Owing to the multiple functions, there are conflicting demands on wood anatomy depending upon environmental and architectural forces that change according to the structure (trunk/branch) in which functional traits are estimated. In this context, we explored how the mean values, variability and correlation patterns of wood anatomy traits varied between trunks and branches. We measured seven wood traits related to hydraulic efficiency and safety and mechanical support in 19 tree species that are widely distributed in tropical dry forests in Colombia. We found higher mechanical support and hydraulic efficiency in trunks than in branches and higher variation in hydraulic traits when compared to mechanical wood traits in both trunks and branches. We also detected higher traits coupling in branches when compared to trunks. Our results showed that contrasting forces acting over trunks and branches result in substantial intra-individual variability. These results are an important contribution when addressing ecological questions relating to the identification of functional strategies, species' response capacity to changing environmental conditions and aboveground biomass estimations.