O objetivo dessa pesquisa foi verificar mudanças na cobertura vegetal de parte da Reserva do Alto Rio Guamá em Paragominas, PA, por meio de índices de vegetação, visando elaborar um panorama multitemporal da degradação ambiental. As imagens foram obtidas da base do INPE e a aquisição de bases vetoriais na base do IBGE. O processamento de imagens foi realizado com o programa ENVI 4.7, onde se utilizou as bandas R5, G4 e B3 para as imagens de 1991 e 2010 e as bandas 6R, 5G e 4B para a imagem de 2016. Foi realizada a reprojeção, recorte por máscara e retificação geométrica por pontos de controle. A classificação do índice de vegetação por diferença normalizada (NDVI) considerou as classes água, sem vegetação, gramíneas, capoeira, floresta secundária e floresta densa, para gerar os índices por área (ha). No intervalo de aproximadamente 25 anos houve redução da cobertura florestal, possivelmente pela expansão de atividades agropecuárias e extração de madeira.
Projection techniques of the diametric structure, such as Transition Matrix and Movement Ratio, have been frequently used in Araucaria Forest, but there is no information about the potential of the Wahlenberg method. In addition, studies on the subject hardly had enough data to assess projections with observed data. Thus, the objective herein was to evaluate the Transition Matrix, Movement Ratio and Wahlenberg Methods in projecting the diametric structure in a Mixed Ombrophylous Forest in the Center-South region of Paraná, Brazil, and compare the projections with observed data. The study was carried out with data from 25 permanent plots of one hectare each, installed in the National Forest of Irati. The measurements of these plots occurred every three years, from 2002 to 2017, covering 15 years of monitoring. The database applied to the three methods used measurements from two periods: three years (2002-2005) and six years (2002-2008). With this, the projections were made for multiple periods, which enabled comparing them with the observed data. The accuracy of the generated projections was assessed by the Kolmogorov-Smirnov test and the Reynolds Index. It was observed that there was a reduction tendency in the projection of the total number of trees in the forest for the three tested methods in the analyzed periods. Among the analyzed methods, the Transition Matrix was more accurate, with an interval of three years (until 2011) and six years. However, it should be noted that the method still has limitations of use in relation to the time between projections.
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