Dinâmica da regeneração natural de espécies arbóreas em ambiente de borda e interior em floresta atlântica, Pernambuco, Brasil

Abstract

The study of natural regeneration and its dynamics is a relevant topic for the preservation, conservation and recovery of forests. The main purpose of this research was to study the dynamics of the natural regeneration of tree species in the border and interior environment of a fragment of Dense Rain Forest, called Mata do Engenho Camurim, with a total area of 243.40 ha. Municipality of Paudalho, state of Pernambuco, Brazil. In order to evaluate the dynamics of natural regeneration, we used data from the structure and floristic composition of the natural regeneration collected in the same fragment in 2013 by Torres (2014) and compared with data obtained in 2016. Data were collected in 80 permanent plots of 25 m² (5 x 5 m) installed in 2013, with 40 plots in each environment. Within the plots, the heights and circumferences of the base (CAB 0,30m) were measured for individuals whose inclusion level was greater than 1.0 m in height and less than 15.0 cm in circumference at chest height (CAP 1.30m). Three size classes were considered to classify regenerative individuals: Class 1, individuals with height 1 ≤ H ≤ 2 m; Class 2, with height 2 <H ≤ 3 m; And Class 3, with height> 3.0 m and CAP ≤ 15 cm. The respective phytosociological parameters, diversity and equability indices, natural regeneration rate by species, mortality and recruitment, and percentages of loss and gain per year of regenerating vegetation in the two environments were estimated. The floristic composition results showed that Fabaceae, Sapindaceae and Myrtaceae were the families with the highest species richness. In phytosociology, it can observed that the species with the greatest wealth of individuals were those that presented the highest values of LV for both environments and the same behavior was observed with the RNT. Regarding the successional classification, the initial secondary species were those that presented the highest percentage in the study area. The TRN by species showed a decrease, between 2013 and 2016, in the density of the pioneers in both the edge and the inland environment. The size classes 1 and 2 presented negative values of NRT for both environments, influenced by the high mortality. In both settings, the mortality rate values were higher than the values of the recruitment rate. In the T test, the variables of the environments: number of individuals, mortality, recruitment and growth in the basal area did not present significant differences.