Functional leaf traits of 57 woody species of the Araucaria Forest, Southern Brazil

The objective of this study was to evaluate the leaf morphology of 57 tree species to determine if there is a dominant leaf pattern in a remnant of the Araucaria Forest, Curitiba, PR, Brazil that can be used as ecological indicator of this forest. We also determined the quantitative morphological and anatomical traits of all species, distributed in 4 different strata, to identify a dominant leaf type of each stratum, regarding light exposure. Thirty mature leaves were collected for each species and were classified morphologically. Leaf area and size, dry mass, specific leaf area, stomata density, total thickness of leaf blade, epidermis, palisade, and spongy parenchyma thickness were also analyzed. Leaves with entire margin, acuminate apex, and microphyllous were predominant among the studied species. All of them presented hypostomatic leaves, except Araucaria angustifolia. All 57 species presented thin leaves and high specific leaf area, indicating mesophyll, characteristic of rain forests as observed in studies in similar dense forests. Low light intensity, in understory species, appears to be determinant of leaf morphology and anatomy differences, associated to high rainfall and relatively low temperature of the study area, both being the characteristics of this Atlantic Forest formation. Considering the results, no specific leaf pattern for the Araucaria Forest was found. Only the lowest stratum showed more differences comparing with the others, and no specific leaf trait could be correlated to light exposure in the present study.