Francisco Tarcísio Alves Junior

DYNAMICS AND PREDICTION OF DIAMETRIC STRUCTURE IN TWO ATLANTIC FOREST FRAGMENTS IN NORTHEASTERN BRAZIL

Monitoring analyses aim to understand the processes that drive changes in forest structure and, along with prediction studies, may assist in the management planning and conservation of forest remnants. The objective of this study was to analyze the forest dynamics in two Atlantic rainforest fragments in Pernambuco, Brazil, and to predict their future forest diameter structure using the Markov chain model. We used continuous forest inventory data from three surveys in two forest fragments of 87 ha (F1) and 388 ha (F2). We calculated the annual rates of mortality and recruitment, the mean annual increment, and the basal area for each of the 3-year periods. Data from the first and second surveys were used to project the third inventory measurements, which were compared to the observed values in the permanent plots using chi-squared tests (a = 0.05). In F1, a decrease in the number of individuals was observed due to mortality rates being higher than recruitment rates; however, there was an increase in the basal area. In this fragment, the fit to the Markov model was adequate. In F2, there was an increase in both the basal area and the number of individuals during the 6-year period due to the recruitment rate exceeding the mortality rate. For this fragment, the fit of the model was unacceptable. Hence, for the studied fragments, the demographic rates influenced the stem density more than the floristic composition. Yet, even with these intense dynamics, both fragments showed active growth.

Regeneração natural em um remanescente de caatinga com diferentes históricos de uso no agreste pernambucano

The objective of this work was to compare a natural regeneration of two areas with Caatinga vegetation with different histories of use in the Agreste of Pernambuco. These studies were carried out in two areas: Area l, native forest, with no historical evidences of deforestation for agriculture purposes; and Area ll, which was previously occupied with the cultivation of forage cactus and was abandoned about 30 years ago at the stage of secondary succession. For data collection, it was used a total of 24 plots of 5 x 5 m dimensions, 12 plots in each area, and considering the plants with circumference at breast height (CBH) of 1.30 m from ground (CAP) 1.0 m as individuals in natural regeneration. It was identified in the structure survey of regenerating individuals structural survey in both areas, 581 plants of 14 botanical families, 26 genus and 30 species. The total densities obtained in this study were 11,200 and 8,116 individuals.ha-1 in Area l and ll, respectively. The species with the greatest densities of natural regeneration

Diameter distribution in a Brazilian tropical dry forest domain: predictions for the stand and species

Currently, there is a lack of studies on the correct utilization of continuous distributions for dry tropical forests. Therefore, this work aims to investigate the diameter structure of a brazilian tropical dry forest and to select suitable continuous distributions by means of statistic tools for the stand and the main species. Two subsets were randomly selected from 40 plots. Diameter at base height was obtained. The following functions were tested: log-normal; gamma; Weibull 2P and Burr. The best fits were selected by Akaikes information validation criterion. Overall, the diameter distribution of the dry tropical forest was better described by negative exponential curves and positive skewness. The forest studied showed diameter distributions with decreasing probability for larger trees. This behavior was observed for both the main species and the stand. The generalization of the function fitted for the main species show that the development of individual models is needed. The Burr function showed good flexibility to describe the diameter structure of the stand and the behavior of Mimosa ophthalmocentra and Bauhinia cheilantha species. For Poincianella bracteosa, Aspidosperma pyrifolium and Myracrodum urundeuva better fitting was obtained with the log-normal function.

Predicting of biomass in Brazilian tropical dry forest: a statistical evaluation of generic equations

Dry tropical forests are a key component in the global carbon cycle and their biomass estimates depend almost exclusively of fitted equations for multi-species or individual species data. Therefore, a systematic evaluation of statistical models through validation of estimates of aboveground biomass stocks is justifiable. In this study was analyzed the capacity of generic and specific equations obtained from different locations in Mexico and Brazil, to estimate aboveground biomass at multi-species levels and for four different species. Generic equations developed in Mexico and Brazil performed better in estimating tree biomass for multi-species data. For Poincianella bracteosa and Mimosa ophthalmocentra, only the Sampaio and Silva (2005) generic equation was the most recommended. These equations indicate lower tendency and lower bias, and biomass estimates for these equations are similar. For the species Mimosa tenuiflora, Aspidosperma pyrifolium and for the genus Croton the specific regional equations are more recommended, although the generic equation of Sampaio and Silva (2005) is not discarded for biomass estimates. Models considering gender, families, successional groups, climatic variables and wood specific gravity should be adjusted, tested and the resulting equations should be validated at both local and regional levels as well as on the scales of tropics with dry forest dominance.

Richness and diversity of Caatinga areas in different successional stages in northeastern Brazil

In northeastern Brazil, areas converted for pasture and agriculture are often abandoned; therefore the recovered areas contain vegetation at different successional stages. The aim of this study was to characterize the diversity and structure of Caatinga vegetation areas with different histories of use in northeastern Brazil. Two areas were used: 1) preserved with no historical evidence of deforestation for agricultural purposes; and 2) regenerated after cultivation of Opuntia ficus-indica Mill., approximately 30 years ago. In each area, vegetation of 12 plots was collected, considering all individuals with circumference at 1.30 m above ground level (CAP) ≥ 6.0 cm. Collected species were classified according to dispersal strategy into the categories of anemochoric, zoochoric, and autochoric. For the analysis of α diversity, species richness, Shannon index, Pielou’s evenness, and Simpson’s index were used. β diversity was evaluated using hierarchical cluster analysis. Structural analysis using density, basal area, and value of importance (VI) was conducted. A comparison between the diameter distributions of the areas was performed using the Kolmogorov– 1PhD. Professor at Department of Forestry Science. UFRPE Universidade Federal Rural de Pernambuco. Rua Dom Manoel de Medeiros, s/n, Dois Irmãos, CEP 52171-900, Recife, PE. E-mail: rinaldo.ferreira@ufrpe.br; jaaleixo@uol.com.br. 2MSc. Professor. UNEC Centro Universitário de Caratinga. Moacyr de Mattos, 87 – Centro 35300-047, Caratinga, MG, Brasil. E-mail: shirleyoliveira10@yahoo.com.br. 3PhD. Researcher. IPA Instituto Agronômico de Pernambuco. General San Martin, 1371, Bongi 50761-000, Recife, PE. E-mail: mariolira@terra.com.br 4PhD. Professor at Department of Production Engineering. UEPA Universidade do Estado do Amapá. Getúlio Vargas, 650, Central 68900-070, Macapá, AM. E-mail: tarcisioalvesjr@yahoo.com.br. 5PhD. Researcher at Jardim Botânico. PCR Prefeitura do Recife. Getúlio Vargas, s/n, BR-232, Km 14 Curado, Recife,PE. E-mail: ladivania@hotmail.com. Ferreira et al. – Richness and diversity of Caatinga areas in different successional stages in northeastern Brazil 800 Sci. For., Piracicaba, v. 44, n. 112, p. 799-810, dez. 2016 DOI: dx.doi.org/10.18671/scifor.v44n112.02 Smirnov test. Indicator species analysis (ISA) was conducted to identify the species preferences per area. The relationship of β diversity with the differences in the composition of species and their densities were analyzed with TWINSPAN. The two areas showed significant differences (p < 0.05) in richness, density, and basal area. There was no significant difference in diversity. Cluster analysis indicated the formation of two floristic groups (40% dissimilarity), which was corroborated by TWINSPAN and ISA. The regenerating area after 30 years of abandonment showed similar species diversity as did the preserved area; however, floristic composition, species richness, density, and basal area did not recover. The similarity in diameter distributions between areas indicated that the abandoned area is recovering its regenerative capability.