Digital aerial photogrammetry (DAP) data acquired by unmanned aerial vehicles (UAV) have been increasingly used for forest inventory and monitoring. In this study, we evaluated the potential of UAV photogrammetry data to detect individual trees, estimate their heights (ht), and monitor the initial silvicultural quality of 1.5-year-old Eucalyptus sp. stand in northeastern Brazil. DAP estimates were compared with accurate tree locations obtained with real time kinematic (RTK) positioning and direct height measurements obtained in the field. In addition, we assessed the quality of a DAP-UAV digital terrain model (DTM) derived using an alternative ground classification approach and investigated its performance in the retrieval of individual tree attributes. The DTM built for the stand presented an RMSE of 0.099 m relative to the RTK measurements, showing no bias. The normalized 3D point cloud enabled the identification of over 95% of the stand trees and the estimation of their heights with an RMSE of 0.36 m (11%). However, ht was systematically underestimated, with a bias of 0.22 m (6.7%). A linear regression model, was fitted to estimate tree height from a maximum height metric derived from the point cloud reduced the RMSE by 20%. An assessment of uniformity indices calculated from both field and DAP heights showed no statistical difference. The results suggest that products derived from DAP-UAV may be used to generate accurate DTMs in young Eucalyptus sp. stands, detect individual trees, estimate ht, and determine stand uniformity with the same level of accuracy obtained in traditional forest inventories.

Knowing the aboveground biomass (AGB) stock of tropical forests is one of the main requirements to guide programs for reducing emissions from deforestation and forest degradation (REDD+). Traditional 3D products generated with digital aerial photogrammetry (DAP) have shown great potential in estimating AGB, tree density, diameter at breast height, height, and basal area in forest ecosystems. However, these traditional products explore only a small part of the structural information contained in the 3D data, thus not leveraging the full potential of the data for inventory purposes. In this study, we tested the performance of 3D products derived from DAP and a technique based on Fourier transforms of vertical profiles of vegetation to estimate AGB, tree density, diameter at breast height, height, and basal area in a secondary fragment of Atlantic Forest located in northeast Brazil. Field measurements were taken in 30 permanent plots (0.25 ha each) to estimate AGB. At the time of the inventory, we also performed a digital aerial mapping of the entire forest fragment with an unmanned aerial vehicle (UAV). Based on the 3D point clouds and the digital terrain model (DTM) obtained by DAP, vertical vegetation profiles were produced for each plot. Using traditional structure metrics and metrics derived from Fourier transforms of profiles, regression models were fit to estimate AGB, tree density, diameter at breast height, height, and basal area. The 3D DAP point clouds represented the forest canopy with a high level of detail, regardless of the vegetation density. The metrics based on the Fourier transform of profiles were selected as predictors in all models produced. The best model for AGB explained 93% (R2 = 0.93) of the biomass variation at the plot level, with an RMS error of 9.3 Mg ha−1 (22.5%). Similar results were obtained in the models fit for the tree density, diameter at breast height, height, and basal area, with R2 values above 0.90 and RMS errors of less than 18%. The use of Fourier transforms of profiles with 3D products obtained by DAP demonstrated a high potential for estimating AGB and other forest variables of interest in secondary tropical forests, highlighting the value of UAV as a low-cost tool to assist the implementation of REDD+ projects in developing countries like Brazil.

RESUmO: As atividades humanas e os usos múltiplos das bacias hidrográficas produzem impactos nos ecossistemas, provocando a deterioração da qualidade das águas e prejuízos aos seus usos preponderantes, bem como podem causar prejuízos à saúde da população, por meio do consumo direto ou do contato primário da exposição a águas contaminadas. Desta forma, o objetivo desse trabalho é propor um índice de qualidade de água, buscando sua interação com parâmetros que possam aumentar a segurança na confiabilidade dos resultados, de forma a preservar a saúde da população, como também contribuir para fomentação de medidas de monitoramento e gestão da qualidade das águas superficiais das bacias hidrográficas e reservatórios pelas agências de controle. Nesse estudo foram utilizados dados secundários disponíveis no Relatório de Monitoramento da Qualidade da Água de Reservatórios do Estado de Pernambuco do ano de 2008 realizado pela Agência Estadual de Meio Ambiente e Recursos Hídricos-CPRH, através do convênio com a Secretaria de Recursos Hídricos-SRH. Dentro desse contexto, foi proposto o Índice de Qualidade de Água Bruta para Abastecimento Público (IQABP), o qual foi criado a partir da inclusão na fórmula do IQA-CETESB do parâmetro Densidade de Cianobactérias, utilizando as faixas de números de células de cianobactérias e a sua respectiva taxação, usadas no cálculo do Índice de Substâncias Tóxicas e Organolépticas (ISTO)-CETESB. Os resultados do monitoramento dos 111 reservatórios recalculados com a nova fórmula indicaram valores mais representativos da preservação ambiental do manancial, refletindo a real condição de qualidade da água do reservatório estudado, demonstrando que quando o IQABP indicar água para abastecimento público de boa qualidade, a população terá a garantia que a toxicidade provocada pelas florações tóxicas de cianobactérias, estará dentro dos limites estabelecidos pela legislação vigente.

RESUMOEste estudo teve como objetivo avaliar a regeneração natural em três áreas de cerradão sob diferentes tipos de interferência, em Jataí -GO. Foram alocadas 30 parcelas de 5 x 5 metros, sendo 10 em cada área. Estas áreas foram denominadas como preservada, pastoreio e queimada. Foram levantados todos os indivíduos com DAP ≤ 5 cm e altura ≥ 30 cm. As espécies foram classificadas quanto a composição florística e a diversidade da regeneração natural foi estimada pelo índice de diversidade de Shannon e pelo índice de equabilidade de Pielou. Para avaliar as possíveis diferenças entre as médias das variáveis: densidade, diâmetro médio à altura do solo, altura média e riqueza nas áreas em diferentes condições avaliadas (preservada, queimada e pastoreio), aplicou-se o Teste t (p<0,05). Nas áreas que sofreram interferência (pastoreio e queimada), as plantas em regeneração natural tiveram menor desenvolvimento em altura e diâmetro em relação a área preservada. A interferência do gado nos fragmentos de cerradão estudados é mais impactante. PALAVRAS-CHAVE: cerradão, conservação, impacto ambiental. EVALUATION OF NATURAL REGENERATION OF CERRADO IN DIFFERENT CONDITIONS OF DISTURBANCE IN JATAÍ-GOABSTRACT The objective of this study was to evaluate the natural regeneration in three areas of forested savanna under different types of interference, in Jataí -GO. 30 plots of 5 x 5 meters were allocated, of which 10 in each area. These areas were designated as preserved, grazing and burned. All individuals with DBH ≤ 5 cm and height ≥ 30 cm were evaluated. The species were classified as floristic composition and the diversity of natural regeneration was estimated by the Shannon diversity index and the Pielou equability index. The t-test (p <0.05) was applied to evaluate the possible differences between the means of the variables density, mean diameter at ground level, average height and richness in the areas under different conditions (preserved, burned and grazing). In the areas that underwent interference (grazing and burning), the plants in

This research was conducted in wood harvesting and transportation areas in the mountainous region of Espírito Santo, Brazil, aiming to analyze the road transportation of forestry wood operations with self-loading trucks. The study identified and evaluated the times, average speed, mechanical availability, level of use and operating efficiency of three different designs of self-loading trucks. According to the results, there was no statistical difference between the vehicles regarding average speed. The highest mechanical availability was found in truck A (93.2%), followed by B (84.3%) and C (79.8%). The greater degree of utilization was found in truck B (91.8%), with little variation between vehicles C (90.0%) and A (89.9%). The highest operating efficiency was observed in truck A (83.9%), followed by B (77.4%) and C (71.8%). We concluded that self-loading truck A was the most efficient.