Influence of leaf morphometric variations on the growth of seedlings and juveniles of woody species in a semiarid environment

Variations in leaf morphometry and in diameter and height growth of plants may occur due to changes in light and temperature conditions of the forest in order to compensate the stress in the habitat. In this study, we examine the relationship of seedling and juvenile size and leaf area of woody species in forests of different ages (>55 and 19 years) in northeastern Brazil. A total of 600 individuals of four species, seedlings and juveniles that survived a rainy season were evaluated. Seedlings and juveniles of Croton blanchetianus Baill, Poincianella pyramidalis (Tul.) L. P. Queiroz, Myracrodruon urundeuva Allemao and Commiphora leptophloeos (Mart.) J.B. Gillett were measured for height and stem diameter in the beginning of the rainy season of 2014. One leaf of each individual was collected in the beginning of the rainy season. Leaves were photographed, and leaf area was measured. Differences in height, diameter and leaf area between forests and the existence of a relationship of diameter and height to leaf area were examined. Leaf area and seedling and juvenile size of C. blanchetianus and C. leptophloeos decreased as succession progressed. However, this was not observed for seedlings of P. pyramidalis and juveniles of M. urundeuva. Leaf area explained 7–26% of the variation in size of individuals in the young forest and 11–39% of the variation in size of individuals in the mature forest. Despite variations in leaf area, significant changes in growth rate were not found with the increase in forest age for most ontogenetic stages and species.