Abstract Fire behavior prediction models can assist environmental agencies with fire prevention and control. This study aimed to adjust a fire prediction model for the state of Minas Gerais, Brazil. Using the R program and hotspots provided by the National Institute for Space Research (INPE) for 2010, prediction of the probability of fires through the Random Forest algorithm was conducted using the Bootstrapping method. The model generated a prediction map with global kappa value of 0.65. External validation was performed with hotspots in 2015. Results showed that 58% of the hotspots are in areas with ignition probability > 50%, being 24% of them in areas with 25-50% probability, and 17% in areas with < 25% probability. These results were considered satisfactory, demonstrating that the model is suitable for predicting fires.

RESUMO Os objetivos deste estudo foram avaliar e correlacionar dados do banco de sementes do solo e do dossel (abertura de dossel-% Canopy Openness e índice de área foliar-IAF) em uma área minerada em processo de restauração por regeneração natural. A área de estudo localiza-se na Zona da Mata Mineira, que apresenta predomínio de Florestas Estacionais Semideciduais, e possui área de 0.50 ha em processo de regeneração natural após 6 anos da exploração de bauxita (sem nenhuma intervenção). Foram plotadas 10 parcelas de 45x29cm ao longo da área, distribuídas de forma a representar toda a porção em processo de restauração. Nestas parcelas foram avaliadas a diversidade do banco de sementes e as características de dossel, estas últimas coletadas através de uma câmera fotográfica NIKON D40X com lente de 8 mm (fisheye). Como resultados foram encontrados 8.280 indivíduos arbóreos, arbustivos, herbáceos e trepadeiras, totalizando 51 espécies e 24 famílias botânicas. O índice de diversidade de Shannon (H’) foi 2,770 e a equabilidade (J) foi 0,705, demonstrando assim uma média diversidade florística desta área, com densidade de 2.114,94 sementes germinadas m-². Através da análise do banco de sementes verificou-se a presença de espécies exóticas na área (23,5%), domínio de espécies pioneiras (68,6%), assim como a predominância de espécies dispersas por anemocoria (52,9%). Quanto às características do dossel, verificou-se uma grande variação existente em diferentes pontos da área, podendo também ser identificado certos padrões de existência de determinadas espécies herbáceas em função da abertura do dossel (menor cobertura vegetal/clareiras), bem como em função da proximidade espacial entre as parcelas plotadas, comprovando assim a alta correlação entre estas duas variáveis e sua importância no processo de restauração florestal.

ABSTRACT The objective of this study was to evaluate and correlate information about soil seed bank and canopy (%Canopy Openness and Leaf area index-LAI) in a mined area in restoration process through natural regeneration. The study area is located in Zona da Mata of Minas Gerais, which presents predominance of Semideciduous Seasonal Forest, and has an area of 0.5 ha in process of natural regeneration after six years of bauxite exploitation (without any intervention). Along the area, ten plots of 45x29cm were allocated and distributed in the best way to represent the whole area in restoration process. Seed bank diversity and canopy characteristics were evaluated in these plots, the last one using a NIKON D40X photographic camera, with fisheye lens of 8mm. As results, 8280 individuals (tree, shrub, herbs, and vines) were found, totaling 51 species and 24 botanical families. The Shannon diversity index (H’) was 2.770, and the equability (J) was 0.705, which demonstrate an average diversity in this area, with a density of 2114.94 germinated seeds m-2. Through the evaluation of the seed bank, the presence of exotic species (23.5%), the dominance of the pioneer species (68.6%), as well as high dispersal by wind (52.9%) were verified in the area. According to canopy characteristics, a significant variation between different points/regions within the study area was found, while patterns of existence of certain herbs as a function of canopy openness (lower vegetal cover/clearings) were also identified, as well as in response to spatial proximity between the allocated plots, confirming the high correlation between these two variables and their importance in the process of forest restoration.

ABSTRACT Alteration of a natural ecosystem can physically, chemically and biologically affect a determined area. Therefore, this study aimed to evaluate the relation between the hydrology, soils and vegetation existing in an area changed by the implantation of a Hydroeletric Power Plant (HPP) in the municipality of Roque Gonzales, Rio Grande do Sul state. The study area was composed of three samples located downstream of the dam. This analysis was performed by the points method to verify the existence of similarity patterns between the vegetation, inundation levels and edaphic soil characteristics of each sample. As a result, greater floristic similarity was observed between the species as a relation of the spatial location with inundation levels. Thus, we can conclude that the vegetal establishment in the study area is under the direct influence of waterflow variation levels from the HPP, which contributes to defining species adaptability to these specific conditions, among others.

A massa específica básica (MEb) é um dos principais parâmetros das propriedades da madeira. Considerando isso, este estudo teve por objetivo avaliar a variação longitudinal da MEb da madeira de Cordia americana (Linnaeus) Gottshling & J.E. Mill e de Alchornea triplinervia (Sprengel) Müller Argoviensis. As árvores foram selecionadas em um fragmento de Floresta Estacional Decidual Aluvial, em Iraí-RS, que, após o abate, foram medidas e cubadas pelo método de Smalian. Para a determinação da MEb, foram retirados discos nas posições da base, 25, 50, 75 e 100% da altura comercial e no diâmetro à altura do peito (DAP), 1,30 m do solo. Os resultados indicaram que a MEb da madeira de Alchornea triplinervia (S.) apresentou padrão homogêneo no sentido longitudinal do fuste; diferentemente da variação encontrada para Cordia americana (L.), em que os maiores valores dessa característica foram observados na base, com tendência decrescente até o topo das árvores.

The specific gravity (MEb) is one of the main parameters of wood properties. Considering that, this study aimed to evaluate the longitudinal variation of the basic density of the wood of Cordia americana (Linnaeus) Gottshling & J.E. Mill and Alchornea triplinervia (Sprengel) Müller Argoviensis. The trees were selected in a fragment of subtropical semideciduals forest (local name Floresta Estacional Decidual), in Iraí-RS, Brazil that, after logging, were measured and scaled by the method of Smalian. To examine the wood density, discs were collected with about two centimeters at positions base, 1.3 m (DBH), 25, 50, 75 and 100% of the height along de stem. Two wedges being withdrawn symmetrical and opposite, which was obtained green volume, wood saturated and dry weight in an oven at 103C (±2°C). Alchornea triplinervia (S.) showed homogeneous wood density in the longitudinal direction of the stem, and Cordia americana (L.) had decreased wood density towards base-top.