Silvana Lages Ribeiro Garcia

Parâmetros morfológicos na avaliação da qualidade de mudas de eucalyptus grandis

An experiment was carried out to study the morphological parameters used to evaluate the quality of Eucalyptus grandis seedlings produced in different tube sizes. A mixture of 80% organic compound (CO) and 20% charcoal powder fertilized with and without N, P and K was used as substrate. Four sizes of hard plastic tubes at the volumes of 50, 110, 200 and 280 cm 3 were used as packaging. Height and height/weight relationship of the aerial part dry matter should be considered, since although providing a satisfactory contribution to seedling quality pattern, the parameters did not present a destructive process. The use of height only to estimate the quality of Eucalyptus grandis seedlings in the 110 cm 3 volume tube when they were 90-day old should be used, since it presents a satisfactory relative contribution, besides being a nondestructive, easily determined and measured parameter.

Avaliação do ajuste das funções weibull e hiperbólica a dados de povoamentos de eucalipto submetidos a desbaste

The objective of this study was to evaluate the Weibull and Hyperbolic fitting functions for describing the diametric structure of eucalyptus stands submitted to thinning. The four- and three-parameter functions were fit to data of 48 permanent plots set up in a thinned eucalyptus hybrid clone (Eucalyptus grandis x Eucalyptus urophylla) stand located in northeastern Bahia. The fitting of the two-parameter Weibull function was also evaluated by linear approximation. Adherence was evaluated by the Kolmogorov-Smirnov test. The sum of squares of the residues (SSR) from the different fittings also was compared. All the functions presented adherence to the data (P>0.01). The hyperbolic function presented the smallest sum of squares of the residues and smallest adherence test values. The Weibull function, when fit by linear approximation, presented the largest sum of squares of the residues and significance values for the adherence test.

Análise comparativa das características da serrapilheira e do solo em cafezais (Coffea arabica L.) cultivados em sistema agroflorestal e em monocultura, na Zona da Mata MG

Coffee plants in agroforestry systems is an alternative to full sunlight cultivation, presenting the potential benefits of enhancing soil chemical and physical characteristics, reducing soil erosion, besides maintaining soil moisture for longer periods. This research aimed at comparing the quantity and nutrient concentration in the litter, soil fertility and soil moisture in coffee crops under full sunlight monocrop and in agroforestry systems, at the Zona da Mata, Minas Gerais, Brazil. The research was carried out between January 1999 and May 2000. The agroforestry system, contributed with 6.1 Mg ha-1 year-1 of litter dry matter while the monoculture produced 4.5 Mg ha-1 year-1, which presented higher nutrient content. The litter in monoculture presented higher nutrient content. The agroforestry system presented higher soil moisture content (20-40 cm depth) and K, Ca, Mg, Sum of Basis, Cation Exchange Capacity, Cu and Zn levels in both soil depth, besides lower aluminum saturation and Al values in deeper layer than soil of monocrop coffee. Soil under monoculture presented higher P and organic matter content than agroforestry system.

REDES NEURAIS ARTIFICIAIS PARA ESTIMAÇÃO DO VOLUME DE ÁRVORES

The objective of this study was to propose a methodology by using Artificial Neural Networks (ANN) to reduce the number of trees to be scaled during the process of generating volumetric equations. The data used in this study were originated from measurements of 2,700 trees of clonal eucalyptus plantations located in southern Bahia State, Brazil. The training of ANN was performed in order to obtain networks for estimating the volume with and without bark. As input variables, we used the diameter at breast height (dbh) - 1.30 m, height, and diameter at 0.0, 0.5, 1.0, 1.5, 2.0 and 4.0 m above the ground and the volumes obtained until 2 and 4 m. The accuracy of the method was carried out using the test L & O. We also evaluated the dispersion of percentage errors, frequency histogram of the percentage error and the root mean square error (RMSE). The methodology proposed in this study proved to be efficient for estimating the volume of trees, and is indicated to obtain the total volume with and without bark of eucalyptus, enabling the reduction of costs for the construction of volumetric equations.

Modelos de distribuição diamétrica para povoamentos desbastados de eucalipto utilizando a função hiperbólica

The objectives of this study were to adjust, to employ and to propose diameter distribution models with different hyperbolic function shapes for the projection of the diameter distribution of thinned stands. It was used data from an experiment on thinning set up in three stands of an Eucalyptus grandis × Eucalyptus urophylla hybrid, located in the northeastern Bahia state. The permanent plots were measured at 27, 40, 50, 58, 61, 76, 87, 101 and 112, 125, 135, 147 and 160 months, with a thinning carried out at 58 months of age and a second thinning conducted at 130 months of age. The two-parameter function showed the best results of root mean square error (RMSE), bias and bias%.

Eficiência das funções weibull e hiperbólica para descrição de distribuições diamétricas de povoamentos de Tectona grandis

The Weibull probability density functions and Hyperbolic were compared by efficiency for describing the diameter structure of teak stands (Tectona grandis L. f.) undergoing thinning. These functions with three and four parameters were adjusted using data from 98 permanent plots and rectangular (490 m²), located in thinning stand of Tectona grandis in the Brazilian state of Mato Grosso, being measured for 10 years. Adjustments were made by Maximum Likelihood and adherence was assessed by Kolmogorov-Smirnorv test (a = 1%) and also compared to the residual squares sum (RSS) of the various adjustments. All of the functions presented adherence to data by the Kolmogorov-Smirnorv test (a = 1%). The hyperbolic function had lower squares sum of waste and lower values for the adherence test. It was concluded that the hyperbolic function was more efficient to describe the diameter structure of the studied stands.

Estimação do volume de árvores de clones de eucalipto pelo método da similaridade de perfis

RESUMO ‐ Os objetivos deste trabalho foram desenvolver e propor um procedimento para quantificacao do volume de arvores em plantios clonais de eucalipto nao desbastados. Para quantificar o volume de arvores, foram utilizados dados de 2.036 arvores de clones comerciais de eucalipto pertencentes a empresa CAF Santa Barbara, onde foram ajustadas as equacoes de volume de cada estrato, sendo este determinado pela regiao e pelo clone, e as idades dos clones variaram de 4 a 5 anos. Para cada arvore foi ajustado um modelo de afilamento. Posteriormente, foram realizados abates de tres arvores de clones novos, que nao possuiam equacao de volume especifica, sendo uma arvore “pequena”, uma “media” e uma “grande” em termos de dap e altura total. Com as tres arvores cubadas, foi ajustado o modelo de afilamento, considerando-se as tres arvores. De posse das estimativas dos parâmetros, foi calculada uma medida de similaridade com os parâmetros das equacoes de afilamento ajustadas para as 2.036 arvores dos clones comerciais e o parâmetro da equacao do clone novo. A arvore do clone comercial que apresentou o menor valor de distância euclidiana, em comparacao com o clone novo, foi considerada a mais similar; portanto, a equacao de volume desse clone comercial foi usada para estimar o volume de arvores desse novo clone. Tal procedimento foi denominado metodo da similaridade de perfis. Esse metodo pode ser usado para estimar volume de arvores dos clones que nao tem equacoes especificas, gerando estimativas semelhantes ao comparar dados observados e estimados, tanto de arvores individuais quanto de todo um talhao.