ABSTRACT The knowledge and identification of stem forms allow more accurate quantification of timber resources as the volume and knowledge of aspects related to species genetics and environmental factors on tree growth. Therefore, the objective of this study was the development of methodology based on concepts of solids of revolution to identify the different forms along the tree stems; define the most appropriate formulas to compute the volume of each part of the stem; and estimate diameters along the stems (stem taper). For this, data from 27 felled sample trees of Eucalyptus grandis, separated equally into nine diameter classes, with 60 months of age, planted under 3 × 3 meters spacing were used to establish the relationships between the variables and develop the methodology. For the set of sample trees, the basal part of the stems resembled a neiloid, a cone at the center, and a paraboloid at the top. The differences between stem volumes obtained by applying specific formulas for each stem section and those obtained by a single formula for all sections were statistically significant (p-value < 0.05). The proposed methodology provided accurate estimates of diameters outside the bark compared to the diameters estimated by the taper models for most sample trees, showing the potential of using the methodology as an alternative to traditional methods.

RESUMO O conhecimento e a identificação das formas do tronco permitem uma quantificação mais precisa dos recursos madeireiros quanto ao volume e o conhecimento de aspectos relacionados à genética das espécies e aos fatores ambientais no crescimento das árvores. Assim sendo, o objetivo deste estudo foi o desenvolvimento de metodologia baseada em conceitos de sólidos de revolução para identificar as diferentes formas ao longo dos troncos das árvores; definir as fórmulas mais adequadas para calcular o volume de cada parte deles; e estimar os diâmetros ao longo dos troncos (afilamento). Para isso, foram utilizados dados de 27 árvores amostrais de Eucalyptus grandis, separadas igualmente em nove classes de diâmetro, com 60 meses de idade, plantadas no espaçamento 3 × 3 metros, para estabelecer as relações entre as variáveis e desenvolver a metodologia. Para o conjunto das árvores amostrais, verificou-se que a parte basal dos troncos assemelhavam-se a um neilóide; a um cone na parte central; e a um parabolóide no topo. As diferenças entre os volumes do tronco obtidos pela aplicação de fórmulas específicas para cada seção do caule e aqueles obtidos por uma fórmula única para todas as seções foram estatisticamente significativos (p-valor < 0,05). A metodologia proposta forneceu estimativas precisas dos diâmetros com casca em comparação com os diâmetros estimados pelos modelos de afilamento para a maioria das árvores amostradas, mostrando o potencial do uso da metodologia como alternativa aos métodos tradicionais.

ABSTRACT Background: Extensive research seeks to improve forest management by understanding the effects of silvicultural treatments on productivity. Continuous forest inventory (CFI) plots offer valuable data for such studies. However, accuracy relies heavily on the twin plot concept, where two adjacent plots (twins) are established to isolate treatment effects from natural variation. This study explored the validity of the twin plot concept by analyzing data from 191 plot pairs in clonal eucalypt plantations. Specifically, it aimed to assess the equality of production volume and the internal structure between CFI plots and their twin plots. Results: Normality assumptions for plot volume differences were not met, even after applying a transformation procedure. Paired t-tests couldn’t be performed, but the non-parametric Wilcoxon test indicated no statistical difference in plot volumes. However, a different procedure called the L&O test revealed significant statistical differences. Gini coefficients demonstrated variations in tree volume distribution between plot pairs. Limited tree numbers and varying diameter classes prevented the use of Chi-square tests for diameter distribution equality. The Kolmogorov-Smirnov test showed non-adherence to estimated distributions using the Weibull distribution function. The L&O test identified significant differences in diameter distributions in 55 of the 191 plot pairs. Conclusions: We have concluded that it is critical to determine the twin nature of plots during first tree measurement to properly analyze the effects of silvicultural treatments on forest productivity. This requires robust statistical tests, adherence to assumptions, examination of internal plot structures, and adequate plot sizes for modeling diameter distribution.

ABSTRACT Non-destructive tests that use the principle of wave propagation have the potential to predict the mechanical properties of wood while still in the field, if the variables of this process are known. This work aimed to estimate the modulus of elasticity to static bending of Eucalyptus sp. wood, using two non-destructive techniques: ultrasound and stress wave. For this, 60 specimens with nominal dimensions of 2.5 x 2.5 x 57.5 cm (tangential x radial x longitudinal) were used, being in equilibrium humidity. The non-destructive tests were carried out using an ultrasound and a stress wave equipment, while the destructive static bending tests were carried out in a universal testing machine. The experimental results showed that the elastic modulus obtained by the non-destructive techniques were superior to that obtained by the destructive technique. The adjusted mathematical models presented standard error of the estimate (Syx) of 11.39 and 10.78%. There was a positive mean correlation between the static and dynamic module. Stress wave and ultrasound techniques can be used to estimate the modulus of elasticity of Eucalyptus sp.

RESUMO Os ensaios não destrutivos que utilizam o princípio de propagação de ondas têm potencial para predizer as propriedades mecânicas da madeira ainda em campo, se conhecida as variáveis deste processo. Este trabalho teve o objetivo de estimar o módulo de elasticidade à flexão estática da madeira de Eucalyptus sp., por meio de duas técnicas não destrutivas: ultrassom e stress wave. Para tal foram usados 60 corpos de provas com dimensões nominais de 2,5 x 2,5 x 57,5 cm (tangencial x radial x longitudinal), estando na umidade de equilíbrio. Os testes não destrutivos foram realizados por meio de um equipamento de ultrassom e um de ondas de tensão, enquanto que os testes destrutivos de flexão estática foram realizados em uma máquina universal de ensaios. Os resultados experimentais mostraram que os módulos de elasticidade obtidos pelas técnicas não destrutivas foram superiores à obtida pela técnica destrutiva. Os modelos matemáticos ajustados apresentaram erro padrão da estimativa (Syx) de 11,39 e 10,78%. Logo, houve correlação média positiva entre o módulo estático e dinâmico. As técnicas de ondas de tensão e ultrassom podem ser empregadas com o intuito de estimar o módulo de elasticidade da madeira de Eucalyptus sp.

ABSTRACT This work aimed to estimate the basic density of Eucalyptus sp. wood, using the non-destructive ultrasound technique. For this, 113 specimens with nominal dimensions of 2.5 x 2.5 x 57.5 cm (tangential x radial x longitudinal) were used, being in equilibrium humidity. To perform the density estimation, the three-dimensional model that governs the propagation of longitudinal waves in isotropic solids was used. The input variables of the model were determined, being the longitudinal modulus of elasticity by static bending, the Poisson's ratio by numerical methods and the propagation velocity of the ultrasound wave by a non-destructive ultrasound testing equipment. The basic density was also obtained by the hydrostatic balance method as a reference value. The actual average basic density was 595.40 kg.m-3 and the estimated one was 591.21 kg.m-3. The estimated value had a strong correlation with the observed value with r =0.89. The estimation by the three-dimensional model showed a low error with an RMSE of 6.50% and a bias of 0.59%. The estimation of the basic density using this method obtained good precision, being similar to the resistography technique.

RESUMO Este trabalho teve o objetivo de estimar a densidade básica da madeira de Eucalyptus sp., por meio da técnica não destrutiva de ultrassom. Para tal foram usados 113 corpos de provas com dimensões nominais de 2,5 x 2,5 x 57,5 cm (tangencial x radial x longitudinal), estando na umidade de equilíbrio. Para realizar a estimação da densidade, foi usado o modelo tridimensional que rege a propagação de ondas longitudinais em sólidos isotrópicos. Foram determinadas as variáveis de entrada do modelo, sendo o módulo de elasticidade longitudinal por flexão estática, o coeficiente de Poisson por métodos numéricos e a velocidade de propagação da onda de ultrassom por um equipamento de ensaios não destrutivos de ultrassom. Também foi obtida a densidade básica pelo método da balança hidrostática como valor de referência. A densidade básica média real foi de 595,40 kg.m-3 e a estimada de 591,21 kg.m-3. O valor estimado teve forte correlação com o valor observado com r = 0,89. A estimação pelo modelo tridimensional apresentou baixo erro com RMSE de 6,50% e viés de 0,59%. A estimação da densidade básica empregando este método obteve boa precisão, sendo semelhante à técnica de resistografia.

ABSTRACT The objective of this study was to compare different alternatives to estimate the stem volume of individual trees in four different forest formations in the Minas Gerais state, Brazil. The data were obtained in a forest inventory procedure performed by the Minas Gerais Technological Center Foundation. The stem volumes were computed by the Smalian expression up to the outside bark diameter equal to 4 cm. The volume data of outside bark, diameters (DBH) and total heights were used to fit a Schumacher and Hall equation for each forest formation, considering the structures of the linear fixed and mixed models. Next, 100 Multilayer Perceptron artificial neural networks (ANN) were trained in a supervised manner. In addition, we evaluated eight support-vector machine regression (SVMR). The criteria to evaluate the performance of all the alternatives studied were: the correlation between the observed and estimated volumes, the square root of the mean square error and the frequency distribution by percentage relative error class. After the analyzes, all the alternatives were verified to estimate the volume of the individual trees in the different forest formations. Although the alternatives presented close statistics in the validation process, the graphical analysis of the error distribution showed greater precision of the estimates of the mixed linear models for the four formations. Given the results, it is concluded that there is no absolute superiority of one alternative over the others, and that all of them should be evaluated to find the one which best describes or explains the dataset.

Abstract The objective of this study was to assess and compare two methodologies to predict the mortality of individual trees in a seasonal semi-deciduous forest located in the municipality of Viçosa, Minas Gerais, Brazil. The data came from 10 permanent plots and were randomly divided into two groups: fitting (6 plots) and validation (4 plots). When assessing Methodology 1, the mortality was considered a dichotomous variable in a logistic model, assuming a value of 1 for a dead tree and 0 for a living tree. In Methodology 2, the mortality probability was estimated by the group of trees for each plot and for each measurement interval. After the analysis, it was observed that Methodology 2 provided more consistent mortality estimates when compared to the mortality estimated by Methodology 1.

ABSTRACT This paper aimed to estimate the basic density (DB) of the wood of Cerrado species using mixed linear models. For performing the DBH measurement, the sampling of 334 individuals was carried out. By keeping the Pilodyn apparatus in the DBH position, two measurements were made on opposite sides. Further, for determining DB, the trees were knocked down, followed by removal of five wood discs at different height of stem positions. For this purpose, two sets of modeling alternatives were proposed, which take into account with and without random effects, employing species as a random effect grouping variable. Thus, it was elucidated that, for the estimation of DB, the mixed model that considered the random effects performed better as compared to the alternative model without random effects. The inclusion of random effects leads to the estimation of DB with high accuracy.

Resumo Estudos sobre a estrutura vegetacional de fragmentos florestais que consideram o uso pretérito do solo podem contribuir para subsidiar ações conservacionistas e de restauração florestal. A partir disso, objetivamos comparar três sítios de um fragmento florestal com distintas histórias de perturbação e verificar se os mesmos diferem entre si com relação ao estágio sucessional analisando atributos estruturais da vegetação arbórea e abundância de lianas. A área estudada localiza-se no município de Alegre-ES, em uma Floresta Estacional Semidecidual constituída por três sítios com diferentes históricos de uso do solo e idades de pousio que recuperaram-se de corte seletivo (CS), lavoura de café (CC) e pastagem (PA). Utilizamos parcelas (19) de área fixa (20 × 20 m) na amostragem, totalizando 0,76 ha. Os indivíduos arbóreos com DAP ≥ 5 cm e as lianas com DAP ≥ 1 cm foram amostrados. A análise da categoria sucessional demonstrou que os sítios CS e PA possuem estágio mais avançado de sucessão em relação à CC. A espécie de maior VI, síndromes de dispersão e lianas apontaram maior avanço sucessional do sítio PA, área com maior proteção aos efeitos de borda e antrópicos por estar localizada no interior do fragmento florestal. As demais análises não demonstraram diferença entre os três sítios.

Abstract To consider past land use on vegetative structure studies of forest fragments can contribute to conservation and forest restoration actions. From this we aim to compare three sites of a forest fragment with distinct anthropogenic disturbances and to verify if they differ on successional stage through analyses of structural traits (trees) and non-trees abundance (lianas) The studied area is located in the Alegre municipality, ES state, in a semideciduous seasonal forest matrix with different land use history composed of selective cutting (CS), coffee crop (CC) and pasture (PA). At each site, randomly plots were sample (19 total plots, 20 × 20 m each), totaling 0.76 ha. All tree individuals with DBH ≥ 5 cm and liana with DBH ≥ 1 cm were sampled. The successional category showed an advanced stage of succession in the CS and PA sites. The specie with higher VI, the dispersion syndromes and the abundance of lianas showed successional advanced stage only in the PA site, because is located inside the forest fragment providing greater protection from edge effects, and anthropogenic disturbances. The others analyses didn´t showed statistical differences between the three sites.

ABSTRACT The aim of this study was to evaluate the effects of age, site, and density factors on the dynamics of eucalyptus diameter distribution. Data were obtained from a continuous forest inventory measured at different occasions, stratified according to the factors evaluated and adjusted by the three-parameter Weibull function using nonthinned clonal plots of eucalyptus stands located in the Central region of the state of Minas Gerais. In order to evaluate the diameter distribution behavior, asymmetry and kurtosis measures and graphical analysis for fitted curves were used. In general, an increase was observed in diameter amplitudes with aging, as well as with improvement of site productivity and higher densities. The number of trees decreased in the lower classes and increased in the upper classes, resulting in diameter distribution curves, being displaced to the right and flattened with aging.

ABSTRACT The objective of this study was to evaluate the use of the MSI Sentinel-2 and SRTM data to estimate the volume of wood in a Semidecidual Seasonal Forest. Regression equations were fitted based on the remote sensing data, taking into consideration the individual bands and vegetation index of the MSI, elevation values and their derivatives obtained from the SRTM mission and the combination of the data drawn from the MSI and SRTM. RMSE and graphic analysis of residues were used to assess the accuracy of the fitted equations. The best model revealed values of 0.6508 and RMSE of 20.41% in the fit, and of 0.5680 and RMSE of 26.61% in the validation, using the combined MSI and SRTM data as predictors. The volume estimation using spectral data showed satisfactory results, highlighting the importance of topography in the prediction of the volume of wood for the area under investigation.

ABSTRACT: The main purpose of this study was to assess nonlinear models generated by integrating the basal area growth rate to estimate the growth and yield of forest stands. The database was collected from permanent sample units, in Paraopeba county, in the state of Minas Gerais, Brazil. The stands were represented by Eucalyptus camaldulensis × Eucalyptus urophylla hybrid trees, with 3 × 3 meters of spacing. The data were divided into two groups: fitting and validating databases. Two nonlinear models (Strategy A and Strategy B) were developed using differential equations to estimate the basal area growth and yield of the sample units. The logistic model was fitted to estimate the volumetric yield as a function of age, site index and basal area. The efficiency of the systems generated by logistic model and models obtained by differential equations (Strategy A and Strategy B) was also compared to the efficiency of the system estimated by the Clutter model (Strategy C). The projection models used to estimate basal area obtained by differential equations were compatible with forest growth and yield, and the logistic model with covariates was compatible with volumetric growth and yield. Strategy A and Strategy B generated different thinning and harvesting options for different site indices, which is biologically consistent.

RESUMO O objetivo geral deste trabalho foi avaliar o método Neuroevolution of Augmenting Topologies (NEAT) para ajustar os pesos e a topologia de redes neurais artificiais (RNAs) na estimação da altura de árvores em povoamento clonais de eucalipto, bem como comparar com as estimativas obtidas por um modelo hipsométrico de regressão. Para a estimativa da altura total das árvores (Ht), pelas RNAS e pelo modelo de regressão, utilizou-se variáveis diâmetro à 1,3 m de altura (dap) e a altura dominante (Hd). As RNAs foram ajustadas e aplicadas no sistema computacional NeuroForest, variando o tamanho da população inicial (parâmetro do algoritmo genético) e a densidade das conexões iniciais. As estimativas da altura total das árvores obtidas com o emprego de RNA e pelo modelo de regressão foram avaliadas com base no coeficiente de correlação, no gráfico de dispersão dos erros percentuais, no histograma de frequência percentual dos erros percentuais e na raiz do erro quadrado médio percentual (Root Mean Square Error - RMSE). A configuração de tamanho de população 300 e densidade inicial das conexões de 0,1 obteve a maior correlação e o menor RMSE%. Foram encontradas várias configurações de RNA com estatísticas superiores ao modelo hipsométrico de regressão. A metodologia NEAT pode ser utilizada para a estimação da altura de árvores em povoamento clonais de eucalipto.

ABSTRACT The aim of this study was to evaluate the method of neuroevolution of augmenting topologies (NEAT) to adjust the weights and the topology of artificial neural networks (ANNs) in the estimation of tree height in a clonal population of eucalyptus, and compare with estimates obtained by a hypsometric regression model. To estimate the total tree height (Ht), the RNAs and the regression model, we used as variables a diameter of 1.3 m height (dbh) and the dominant height (Hd). The RNAs were adjusted and applied to the computer system NeuroForest, varying the size of the initial population (the genetic algorithm parameter) and the density of initial connections. Estimates of the total height of the trees obtained with the use of RNA and the regression model were evaluated based on the correlation coefficient, the percentage of errors scatter plot, the percentage frequency histogram of percentage errors, and the root mean square error (root mean square error - RMSE). Various settings which resulted in superior statistics to the hypsometric regression model were found. Connections had the highest correlation and the lowest RMSE% with a population size value of 300 and an initial density of 0.1 RNA. The NEAT methodology proved effective in estimating the height of trees in clonal population of eucalyptus.

RESUMO Objetivou-se aplicar e avaliar métodos para estimar múltiplos volumes em uma Área de Manejo Comunitário, localizada na Floresta Nacional do Tapajós. Foram cubadas, rigorosamente, 516 árvores-amostra de 21 espécies comerciais, todas com 50 cm > dap < 160 cm. Utilizaram-se o modelo único para múltiplos volumes (análise de regressão) proposto por Leite et al. (1995) e redes neurais artificiais (RNA) para a estimativa do volume de fuste e galhos. Após os resultados preliminares usando o método de regressão, optou-se por separar os dados em três estratos, considerando a relação volume de galhos em razão do volume de fuste comercial. As equações geradas por estratos apresentaram melhoria nos ajustes, mas os resultados obtidos pela RNA foram melhores que os pelas equações de regressão.

ABSTRACT The objective of this study was to apply and evaluate methods to estimate multiple volumes in a Community Management Area, located in the Tapajós National Forest. 516 sample-trees were rigorously scaled of 21 commercial species, all with 50 cm > dbh < 160 cm. The unique model for multiple volumes (regression analysis) proposed by Leite et al. (1995) and Artificial Neural Networks (ANN) were used to estimate the volume of stem and branches. After preliminary results using the regression method, it was decided to stratify the data into three parts, considering the relationship between volume of branches and volume of commercial stem. The equations generated showed improvement in the adjustments. However, the results with ANN were better than the ones generated by regression equations.

O objetivo deste estudo foi avaliar o rendimento em laminação de madeira de paricá (Schizolobium amazonicum Huber ex. Ducke) em plantios comerciais na região de Paragominas, Pará. A partir de 180 árvores-amostra oriundas de plantios com idades de cinco, seis e sete anos em espaçamento 4 x 4 m, foram avaliados o rendimento médio na atividade levando em consideração os rendimentos por idade e por classe de diâmetro. Foram avaliadas também as perdas em todo o processo de laminação. Os resultados apontaram um rendimento médio de 50,31% na atividade, o que é compatível com espécies dos gêneros Pinus e Eucalyptus. Verificou-se que as árvores com maior idade e diâmetro apresentaram os maiores rendimento e, consequentemente, as menores perdas devido a defeitos e ao rolo-resto.

The aim of this study was to evaluate the performance of laminate wood paricá (Schizolobium amazonicum Huber ex. Ducke) in commercial plantations in the region of Paragominas, Pará state. Using 180 sample trees aged five, six and seven years,originating from plantations and grown in 4 x 4 m spacing, the average income was evaluated, taking into account income by age and diameter class. Losses were also evaluated throughout the lamination process. The results show an average yield of 50.31% in the activity, which is consistent with species of Pinus and Eucalyptus. Trees that were older and larger in diameter showed higher yield and therefore lower losses due to defects and the remainder roller.

Objetivou-se, neste trabalho, avaliar a dinâmica do estoque de carbono no fuste das árvores de uma Floresta Estacional Semidecidual, por meio do monitoramento de 10 parcelas permanentes instaladas na Mata da Silvicultura, Viçosa, Minas Gerais. Foram identificados e medidos todos os indivíduos com DAP ≥ 5 cm, nos anos de 1994, 1997, 2000, 2004 e 2008. O estoque médio de carbono no fuste das árvores aumentou de 47,9 ton.ha-1, no ano de 1994, para 61,81 ton.ha-1, no ano de 2008, representando, para os 14 anos de monitoramento, um incremento periódico de 0,994 ton.ha-1.ano-1.

The objective of this study was to evaluate the dynamics of stem carbon storage in a Semideciduous Forest, through the monitoring of 10 permanent plots established in the Mata da Silvicultura, Viçosa, Minas Gerais. All trees with DBH ≥ 5 cm were identified and measured in the years 1994, 1997, 2000, 2004 and 2008. The stems average carbon storage increased 47.9 ton.ha-1 from the year of 1994 to 61.81 ton.ha-1 in the year of 2008, representing, for the monitoring of 14 years, a regular increase of 0.994 ton.ha-1.year-1.