Modeling the diameter distribution of a fragment of Mixed Ombrophyllous Forest, in Lebon Régis, SC.

The objective of this work was to fit and to select different probability density functions (pdf’s), such as, Normal, Gamma (Adapted), Beta (Adapted), Exponential, Weibull 3P, Johnson Sb, Weber and Péllico Netto, to describe the diameter distribution of all species and the seven species with the highest importance value of a fragment of Mixed Ombrophyllous Forest, in Lebon Régis, SC, Brazil. The data processing was performed using the Solver tool on MS Excel 2007, using the linear algorithm of generalized reduced gradient (GRG) for interaction of parameters. The selection criteria used were the Kolmogorov-Smirnov and statistics of fit and accuracy. According to the results, the function that best represented the diameter distribution considering all species of forest fragment was Johnson Sb. When considered the species individually, the Ln-normal function best described the diameter distribution of Myrcia sp., and Myrsine gardneriana (Aubl.) DC. For Ocotea porosa (Nees & C. Mart.) Barroso., and Araucaria angustifolia (Bertol.) Kuntze., the function with the best adherence was Gamma (Adapted) and Ocotea elegans Mez., Mimosa scabrella Benth., and Styrax Leprosus Hook. & Arn., functions with the best performance were, 3P Weibull, Péllico Netto and Normal, respectively.Keywords: Araucaria Forest; horizontal structure; probability density function.O objetivo deste trabalho foi ajustar e selecionar diferentes funções de densidade de probabilidades (FDP), tais como Normal, Ln-normal, Gamma (Adaptada), Beta (Adaptada), Exponencial, Weibull 3P, Sb de Johnson, Weber e Péllico Netto, para descrever a distribuição diamétrica de todas as espécies e das sete espécies com maior valor de importância de um fragmento de Floresta Ombrófila Mista em Lebon Régis, SC. O processamento dos dados foi realizado por meio da ferramenta “Solver” MS Excel 2007, a qual utiliza o algoritmo linear de gradiente reduzido generalizado (GRG) na interação dos parâmetros. Os critérios de seleção utilizados foram o teste de Kolmogorov-Smirnov e as estatísticas de ajuste e precisão. De acordo com os resultados, a função que melhor representou a distribuição diamétrica considerando todas as espécies do fragmento florestal foi a Sb de Johnson. Quando consideradas as sete espécies individualmente, a função Ln-normal melhor descreveu a distribuição diamétrica de Myrcia sp. e Myrsine gardneriana (Aubl.) DC. Já para Ocotea porosa (Nees & C. Mart.) Barroso e Araucaria angustifolia (Bertol.) Kuntze, a função de melhor aderência foi Gamma (Adaptada), e para Ocotea elegans Mez, Mimosa scabrella Benth. e Styrax leprosus Hook. & Arn., as funções de melhor desempenho foram Weibull 3P, Péllico Netto e Normal, respectivamente.Palavras-chave: Floresta com Araucária; estrutura horizontal; função de densidade de probabilidade. AbstractModeling the diameter distribution of a fragment of Mixed Ombrophyllous Forest, in Lebon Régis, SC. The objective of this work was to fit and to select different probability density functions (pdf’s), such as, Normal, Gamma (Adapted), Beta (Adapted), Exponential, Weibull 3P, Johnson Sb, Weber and Péllico Netto, to describe the diameter distribution of all species and the seven species with the highest importance value of a fragment of Mixed Ombrophyllous Forest, in Lebon Régis, SC, Brazil. The data processing was performed using the Solver tool on MS Excel 2007, using the linear algorithm of generalized reduced gradient (GRG) for interaction of parameters. The selection criteria used were the Kolmogorov-Smirnov and statistics of fit and accuracy. According to the results, the function that best represented the diameter distribution considering all species of forest fragment was Johnson Sb. When considered the species individually, the Ln-normal function best described the diameter distribution of Myrcia sp., and Myrsine gardneriana (Aubl.) DC. For Ocotea porosa (Nees & C. Mart.) Barroso., and Araucaria angustifolia (Bertol.) Kuntze., the function with the best adherence was Gamma (Adapted) and Ocotea elegans Mez., Mimosa scabrella Benth., and Styrax Leprosus Hook. & Arn., functions with the best performance were, 3P Weibull, Péllico Netto and Normal, respectively.Keywords: Araucaria Forest; horizontal structure; probability density function