Resumo em Inglês:

Abstract Accurate biomass models are important tools for estimating biomass and carbon sequestration in forest plantations. Thirty Acacia mangium trees, aged 13 years, were destructively sampled to determine the distribution of aboveground biomass (AGB) in the main tree components. Six allometric models using diameter at breast height (DBH), total height (H) and crown diameter (CD) as independent variables were fitted using weighted nonlinear regression and evaluated through Monte Carlo cross-validation. Acacia mangium trees primarily accumulate biomass in the stem (51.2 - 58.0 %) and branches (24.6 - 31.5 %), and these proportions tend to remain stable across tree sizes. All tree-level variables showed positive correlations with AGB; however, the strongest correlations were observed with DBH and CD. The developed models displayed slightly better predictive accuracy compared to existing ones. These models will contribute to improving the carbon quantification of Acacia mangium forest plantations in the eastern plains of Colombia.

Resumo em Inglês:

Abstract The Brazilian Atlantic Forest has suffered from historical degradation and this work assessed the vegetation structure and soil quality by examining 45 plots divided in three sites in reference ecosystems from Conselheiro Pena-MG, Brazil. We recorded 28 species from 14 families in the tree stratum and 26 species from 13 families in the sapling stratum. We found a clear edaphic-floristic gradient suggesting a strong association between some particular taxa to contrasting edaphic conditions. The tree Astronium urundeuva behaved as a monodominant species, with the highest importance value (IV) in both strata (62.0% in tree, and 31.5% in the sapling strata). In the tree stratum, this species was present in 97.8% of the plots (44 out of 45). This scenario is worrying because this species occurs in a monodominant form in the middle section of the Rio Doce watershed behaving as an invasive species, preventing the colonization of other native species.

Resumo em Inglês:

Abstract The present study aimed to develop taper equations for African mahogany trees in two important ages (near to thinning and near to clear-cut ages), using, respectively, 100 seven-year-old trees were scaled in Minas Gerais and 46 fourteen- and fifteen-year-old trees were scaled in Pará. The fifth-degree polynomial, the polynomials with integer and fractional powers, the Kozak exponential model, and the modified Kozak model were tested. The equations were assessed and, next, the inclusion of a random term in the best equation at tree level was tested. The best resulting equation was selected, and it was validated using the bootstrapping method. The Kozak exponential model and the modified Kozak model were selected, to trees near thinning and near clear-cut age, respectively. Inserting a random term at tree level in the equation improved its estimates by 5.2% and 8.9% for trees near thinning and clear-cut ages, respectively.

Resumo em Inglês:

Abstract The aim of the study was to characterize the microbiological activity of the soil and its relationship with soil attributes in a toposequence under different vegetation covers at the UFRRJ Botanical Garden. Soil samples were collected from the surface layer of the shoulder, backslope and footslope. These show little variation in slope, but have different vegetation cover. The shoulder and footslope are covered by tree species from different botanical families, and the middle third by grasses. The tree species (shoulder) and the grasses (backslope) showed higher values of microbial biomass carbon, soil enzyme activity, sporulation and species richness of arbuscular mycorrhizal fungi. The correlations found suggest the effect of chemical and physical attributes, especially the lower levels of P and coarse sand, on the increase in these soil microbiological attributes. Greater deposition of glomalin-related soil protein was observed in areas with tree species, with correlations with pH and TOC.

Resumo em Inglês:

Abstract Beetles (Coleoptera) are structurally and functionally important in tropical forest ecosystems. The present research aimed to characterize Coleoptera families and Staphylinidae species in areas of native forest and pastures undergoing restoration with nucleation techniques in the Serra do Itajaí National Park. The collections were carried out from pitfall traps, from April/2017 to December/2018. A total of 2619 individuals of Coleoptera were collected, distributed in 30 families, and 637 individuals of Staphylinidae, distributed in 46 species. The abundance, richness, and composition of Coleoptera families and Staphylinidae species varied significantly between native forest and pasture with the inclusion of nucleation techniques for restoration. Microclimate had a significant influence on the ecological parameters analyzed. We identified families and species characteristic of forests and pastures. Less specific taxonomic identification levels showed significant differences, enabling its application as a potential bioindicator of restoration. Our results suggest that pasture areas still support an impoverished leaf litter beetle community.