Dinâmica da vegetação lenhosa em área de caatinga, Floresta – PE

Abstract

The objective of this study was to analyze the dynamics of trees between 2008 and 2011, in an area of savanna (caatinga), 24 years after removal of vegetation by "correntão" in Floresta - PE. The study was conducted at the Itapemirim farm in an area that boasts 50 ha. At the forest inventory were installed 40 permanent plots of 20 x 20 m for adults and 40 sub-plots of 5 x 5 m for natural regeneration, for the dynamics of woody vegetation the data were collected from adults in the years of 2008 and 2011 and for regenerating the data were collected in 2008, 2009, 2010 and 2011. The criterion for inclusion were considered adult individuals who presented to the circumference 1.30m (CBH) ≥ 6 cm, and their bifurcations, since the subjects of natural regeneration were grouped into four height classes: class 1 = 20 to 50 cm, class 2 = 51 to 100 cm, class 3 = 101 to 150 cm, grade 4 = greater than 151 cm and less than 6 cm cap. The evaluated parameters of the individuals measured were: density, frequency and dominance, importance value, classes of natural regeneration, natural relative regeneration, Shannon diversity index and Pielou index, income, mortality and growth. The adults had a total number of 1351 individuals in 2008 and 1680 in 2011, at both times of monitoring, were found eight families, 17 genera and 23 species. As a result there was no change in Shannon diversity index or the Pielou index, remaining at 1.84 nats/ind. and 0.59 on both occasions. The absolute density of the first occasion was 864.38 individuals.ha-1, three years later, the number of individuals rose to 1070.63 individuals.ha-1; measurements in the two species that had higher importance value were Poincianella bracteosa and Jatropha mollissima. The mortality rate exceeded the ingroth of 30.96%. Regenerating individuals were found in five families, nine genera and 10 species, with 96 individuals in the first monitoring, and six families, 12 genera and 13 species with 153 individuals in the last monitoring, so the Shannon diversity index increased from 1.80 nats/ind. to 1.96 nats/ind., the Pielou index did not very much from 0.75 to 0.74 from first to last monitoring. The absolute density of samplings increased by 37.25%. And the species with the highest value of Natural Regeneration in all years monitored was the Thiloa glaucocarpa.