In eucalyptus plantations, the presence of understory increases the risk of fires, acts as an obstacle to forest operations, and leads to yield losses due to competition. The objective of this study was to develop an approach to discriminate the presence or absence of understory in eucalyptus plantations based on airborne laser scanning surveys. The bimodal canopy height profile was modeled by two Weibull density functions: one to model the canopy, and other to model the understory. The parameters used as predictor in the logistic model successfully discriminated the presence or absence of understory. The logistic model composed by g canopy , g understory , and g understory showed higher values of accuracy (0.96) and kappa (0.92), which means an adequate classification of presence of understory and absence of understory. Weibull parameters could be used as input in the logistic regression to effectively identify the presence and absence of understory in eucalyptus plantation.
<p class="MsoNormal" style="margin-bottom: .0001pt; text-align: justify; line-height: 150%;"><span style="font-size: 12.0pt; line-height: 150%; font-family: 'Times','serif'; mso-bidi-font-family: Arial;">O monitoramento ambiental de fragmentos florestais é um trabalho oneroso e demorado, por isso, o sensoriamento remoto (SR) por intermédio do índice de vegetação da diferença normalizada (NDVI) é uma ferramenta eficaz na identificação das áreas florestadas e que sofreram desmatamento. O satélite LANDSAT é uma importante fonte de base de dados para esse tipo de estudo, pois, possui imagens com mais de 29 anos de série temporal, o que possibilitou a criação dos mapas temáticos do Parque Estadual Cachoeira da Fumaça (PECF) localizado no Sul do Estado do Espírito Santo, e a identificação das áreas em que a vegetação arbórea sofreu desmatamento, não sofreu alteração e onde houve regeneração no parque. O PECF apresentou aproximadamente 72% da sua área sem sofrer alteração e 20% da sua área foi regenerada entre os anos de 1985 e 2010, demonstrando eficiência do seu plano de manejo.</span></p>
ABSTRACT:In Brazil, ninety percent of total electric power comes from renewable sources, where hydropower represents 2/3 of the national energy matrix. In 2012, the new Federal Forest Code eliminated environmental protection along drainage divides and reduced the mandatory width of riparian zones, allowing for land cover change in these environmentally sensitive areas. The conversion of forestlands to agriculture will subject hydroelectric reservoirs to a growing load of sediments, shortening their useful life. In this study of the Furnas hydropower plant and its contributing basin, in the upper reaches of the Rio Grande, a re-evaluation of factors that determine the distribution of finances accrued from hydroelectric generation is recommended. Under the current policy, royalties are paid by the Furnas facility to states and municipalities in direct relation to the area of land flooded by its reservoir, whereas contributing rainfall precipitating in municipalities upstream of the lake is not considered. Currently, the 31 municipalities with lands flooded by the reservoir receive an average of R$ 213,107 (US$ 67,226) annually, while the remaining 172 municipalities in the basin receive no water royalties. In the proposed approach to redistribute these funds, each of the 203 municipalities will receive compensation determined by their contributing catchment area, averaging R$32,543 (US$ 10,266) per year. By considering distribution of rainfall in order to equitably allocate hydroelectric royalties, a system for the payment of environmental services is conceived. Such a system intends to incent stakeholders to protect or replant native forests along drainage divides and riparian zones, in recognition of the value this vegetation has in the reduction of long term costs for hydroelectric facilities.
RESUMO As geotecnologias têm sido amplamente empregadas em estudos de alterações na paisagem, como o monitoramento de biomas e da expansão urbana, acompanhamento da evolução do uso da terra, estudos sobre a fragmentação florestal, a cobertura vegetal e a susceptibilidade à erosão, entre tantos outros. O conhecimento do uso e cobertura da terra é considerado fundamental na reversão de um ambiente degradado. Neste sentido, o objetivo deste trabalho foi analisar o processo de evolução do uso e ocupação da terra na bacia hidrográfica do Rio Vieira, localizada no município de Montes Claros, Minas Gerais.
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