Fenologia, regeneração natural e adaptações estruturais de Aspidosperma pyrifolium Mart. em área de caatinga na Mesorregião de Patos - PB.

Abstract

The Caatinga, predominant vegetation of the Semiarid Region presents different faces composed of xerophilous, deciduous and endemic species, that determine its structure. This study aimed to determine the phenology of trees, the growth of regenerating individuals and the structural aspects (cotyledons and lenticels) of individuals of A. pyrifolium in Mesoregion Patos-PB. The study of phenology and regeneration was developed in the period from February to December 2015 at NUPEÁRIDO Farm at coordinates 07º5"10'N and 37º15'43"W. They were selected and identified five adult trees to visit and collect information of phenophases. Rainfall data were collected from the area and soil samples for analysis of soil moisture under the canopy of matrices, following the cardinal points in the layer of 0-15 cm. The study of the natural regeneration of the A. pyrifolium was conducted by monitoring the growth of regenerating individuals in different height classes on a plot of 400 m2. The study of the influence of the cotyledons in the growth of the plants was developed in A. pyrifolium seedling in forestry nursery, evaluating the height (cm) stem diameter (mm) in seedlings submitted at five treatments. The F ANOVA and Tukey's test at 5% significance to compare the means of treatments were applied. The lenticels number of branches was obtained by thirty branches sectioned in apical, middle and basal cuttings with fifteen cm each, in accordance with the relative position of the branch in the trunk of the plant and its fruits from the count in all surface. Means were analyzed using a completely randomized design and applied the ANOVA F test and Tukey's test (5%). At the end of the experiment it was concluded that the phenology of A. pyrifolium proved to be complex and not clearly followed the pattern of rainfall and soil moisture during the study period. Regenerating individuals are underrepresented in the first classes of high and slow growth. The total removal of photosynthetic cotyledons damaged the growth in height and diameter of the plants. The fruits of this species have lots of lenticels and its distribution in the branches occurs in greater proportion in the apical session. It is recommended further studies to better determine these variables and understand their distribution in Caatinga Biome.