Leaf habits and their relationship with leaf and wood traits in tropical dry forests

Key message For better categorization of species according to foliar habit, a set of leaf and wood traits must be observed. Tropical forests are influenced by distinct regional rainfall regimes, microclimates, and dynamics of nutrient cycling, which are responsible for creating key biodiversity patterns and differences in leaf deciduousness to drought. Functional traits studies have improved understanding of the functioning and heterogeneity of complex ecosystems. We have reviewed the literature focusing mainly on tropical dry forests and relationships among leaf habits (evergreen and deciduous) and other leaf and wood traits. Thus, we have compiled 121 original papers, 2 reports, and 9 book chapters published since 2000. We also provide a meta-analysis of these traits from Neotropics. Tropical deciduous species often have high photosynthetic rates per mass and specific leaf area and traits that improve water flow throughout the plant, such as wide xylem diameters and high hydraulic conductivity, maximizing resource capture during a limited growing season because of an acquisition strategy. The opposite is observed in evergreen species, namely as conservative species. Regardless of the plant organ, more morphological than physiological traits are available to compare leaf habits. For better categorization of species according to foliar habit, a set of leaf and wood traits must be observed. However, while local comparisons based on one or few traits may group species according to leaf habit, multivariate analyses for large spatial scales can reveal a different pattern. We have identified some open questions that can be further addressed in this research field to contribute to the improvement of theoretical frameworks as well as the consequences of a changing climate for tropical dry forests.