The aim of this study was to describe the morphology of fruit, seeds and seedlings, as well as the anatomy of the seed and the seedling of Pentaclethra macroloba (Willd.) Kuntze. Morpho-biometry was performed on fifty fruit samples and one hundred seeds. To describe the sequences of the morphological events of the germination stages, ten seeds were placed to germinate. Anatomical analysis was performed in a scanning electron microscope with seed samples and seedling leaves. The species has leguminous type fruit of 16.1 to 45.2 cm length and 4.1 to 7.3 cm width; seeds have a pleurogram and are eurispermic, ovoid, deltoid to elliptical and measure from 3.8 to 6.1 cm length and 2.5 to 5.7 cm width. Anatomically, the cotyledons are composed of thin-walled parenchyma cells with various oil cells. The seedlings have bipinnate leaves, with waxes and simple trichomes at the margins of the adaxial surface and paracytic stomata on the abaxial surface. The epicotyl is slightly twisted, with caducous cataphylls and a first pair of alternate eophylls. Germination is of the phanero-hypogean-reserve type. Taxonomic recognition of this species is possible in the field through the external morphological traits and can help in identification of saplings.

The leaf is a very important plant structure because it allows gas exchange and transformation of light energy into chemical energy. The objective of this research study was to test artificial neural networks (ANNs) to estimate the leaf area (LA) of Ormosia paraensis Ducke and compare their performance with adjusted statistical models. One hundred forty leaves were selected from seedlings of the species at the leaf age of 100 days after sowing (DAT). The LA was calculated by indirect estimation with ImageJ software, and the linear length (L) and width (W) dimensions were measured with a ruler graduated in centimeters. Afterward, 90 leaves were randomly separated to generate mathematical equations of LA (Y) as a function of linear dimensions (L and W), and 50 leaves to validate the equations. Similarly, 100 networks of the multilayer perceptron (MLP) type were trained with the backpropagation algorithm and the best networks were selected for later validation. The choice of the best equations and ANNs was based on precision and dispersion statistics. The quadratic equation obtained from model (4) demonstrated consistent statistics with the coefficient of determination (R²aj = 87.39) and a low result for the standard error of estimate (SEE = 12.07%). For the ANNs, a correlation coefficient (Ryŷ), varying between 0.9316 and 0.9521, was obtained in the training phase, while it ranged from 0.8522 to 0.8825 in the validation phase, generating lower residues. It is concluded that the ANN performance was higher compared with the conventional regression technique.

O objetivo deste estudo foi analisar a variação da estrutura diamétrica de uma comunidade arbórea em floresta densa de terra firme e dos principais grupos de espécies de estágios iniciais e tardios de sucessão, bem como caracterizar a estrutura vertical da floresta. Em 2016, foram inventariadas todas as árvores com DAP ≥ 10 cm e mensuradas suas alturas. Em 2017, as árvores foram reamostradas. A estrutura diamétrica foi analisada por meio do quociente “q” De Liocourt para: a comunidade, principais espécies de maior VI e os grupos ecológicos (GE). A análise da estrutura vertical da vegetação foi feita pela distribuição do número de árvores nos estratos, utilizando-se três métodos: (I) – Sanquetta (1995), (II) - Souza (1990), e (III) – Souza et al. (2003). A estrutura diamétrica da comunidade e dos GE no período avaliado foi caracterizada por árvores de pequeno porte nas menores classes de diâmetro. O Método II não trouxe bons resultados sobre o comportamento das espécies no estrato médio por apresentar fortes tendências em concentrar um maior número de indivíduos nesse estrato. Os resultados da estrutura altimétrica e diamétrica demonstraram indicativos que a exploração antrópica no passado alterou a estrutura da floresta.Palavras-chave: espécies amazônicas, “q” De Licocourt, estratificação, incremento. STRUCTURE AND DYNAMICS IN A DENSE OF TERRA FIRME FOREST, SOUTHEAST OF AMAPÁ, BRAZIL ABSTRACT:The study aimed to analyze the variation of the diameter structure of a arboreal community in a dense terra firme forest and the main groups of species of early and late stages of succession, as well as characterize the vertical structure of the forest. In 2016, all trees with DBH ≥ 10 cm were inventoried and their heights measured indirectly. In 2017, the trees were re-measured. The diametric structure was analyzed using the "q" De Liocourt quotient for: the community, major species of higher (VI) and ecological groups (EG). The analysis of the vertical structure of the vegetation was made by the distribution of the number of trees in the strata, using three methods: (I) – Sanquetta (1995), (II) - Souza (1990), and (III) – Souza et al. (2003). The diametric structure of the community and the EG during the period evaluated was characterized by small trees in the smallest diameter classes. Method II did not bring good results on the behavior of the species in the middle stratum because it presents strong tendencies to concentrate a greater number of individuals in this stratum. The results of the altimetric and diametric structure have demonstrated that antropic exploration in the past has altered the structure of the forest.Keywords: amazonian species, “q” De Licocourt, stratification, increment.

Areas of cerrado (Brazilian savanna) in the Amazon have been poorly studied from the perspective of fire impacts on environmental sustainability, especially with regard to disturbances to soil and vegetation structure. This study aimed to analyze the influence of edaphic variables and fire together on the composition and structure of tree and shrub vegetation of three cerrado remnants in the Amazon. Eight plots were systematically installed in burned and unburned environments in each remnant. Data were submitted to floristic diversity, similarity, and diametric and altimetric structural assessments. Phytosociological parameters were obtained and submitted to Principal Component Analysis (PCA) and Canonical Correspondence Analysis (CCA). A total of 808 individuals (34 species, 30 genera, and 21 families) were recorded. The CCA indicated that the distribution of species is influenced by edaphic factors, as confirmed by the strong direct correlation of tree and shrub species with the reduced nutrition and high acidity of the soils common in the analyzed remnants. Our results support the hypothesis that fire plays a relevant role in structuring vegetation since it contributed to good indicators of soil properties and caused changes in the composition of woody species.

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