Adriano Ribeiro de Mendonça

Modelagem não linear do perfil longitudinal de fustes de Pinus oocarpa

Com o aumento da demanda de produtos florestais no mercado, o incentivo a pesquisas que aperfeicoem a obtencao de multiprodutos das florestas com o menor custo e cada vez maior. Objetivou-se, neste trabalho, avaliar a precisao de um modelo linear (polinomio do 5o grau) e de um modelo nao linear (logistico) na estimativa do perfil do fuste de Pinus oocarpa. A base de dados utilizada foi de um plantio de Pinus oocarpa, localizado no Triângulo Mineiro, originada da cubagem rigorosa de 140 arvores. As equacoes ajustadas foram avaliadas pelos seguintes criterios: criterio de informacao de Akaike, criterio de informacao Bayseiano, analise grafica de residuos e erro padrao da estimativa. O modelo logistico apresentou-se mais preciso na estimativa do perfil do fuste de Pinus oocarpa.

Fuzzy and neuro-fuzzy estimates of the total height of eucalyptus trees

Because of its many uses, including for paper, cellulose, and energy production, the Eucalyptus is an economically important tree. The estimate of eucalyptus total height is useful for forest handling and predicting production. The objective of this work is to study the relation between a eucalyptus trees diameter at breast height (DBH) and age to its total height. Based on this data, we present decision systems developed using fuzzy logic and neuro-fuzzy systems. Both proposed models are compared with classical mathematical models; the neuro-fuzzy system has the highest accuracy and precision.

AVALIAÇÃO DE MODELOS DE AFILAMENTO NÃO-SEGMENTADOS NA ESTIMAÇÃO DA ALTURA E VOLUME COMERCIAL DE Eucalyptus sp.

This work aimed to evaluate different taper models in the estimate of the merchantable height and volume and along the bole volumes of Eucalyptus sp., to the obtention of multiproducts. Considering the data of rigorous scaling of trees of Eucalyptus sp. with 16 years-old, it was appraised the models of taper of Demaerschalk (1972), Ormerod (1973), Schoepfer (1966), Hradetzky (1976), Garay (1979) and Biging (1984). Based on graphical analysis of the residues and on the statistics bias (B), average of the differences (MD) and deviation pattern of the differences (DPD), it could be verified that, in the estimate of the merchantable height and volume of the models, Biging, Schoepfer and Hradetzky presented the best results, followed by the models of Garay, which have also shown good results. In general, considering the treatment of the volumes of the logs, the Biging model presented the best resuts.

Different strategies to estimate the commercial volume of Anadenanthera colubrina (Vell.) Brenan

This work aimed to evaluate the use of traditional models, profile and relative height method, for estimating the commercial volume of Anadenanthera colubrina (Vell.) Brenan. Data were obtained from scaling of separate lengths of the stem of 22 trees, using Smalians method. Tree stems were measured 0.1m, 0.30m, 0.70m, 1.0m, 1.30m above the ground and then every 1m. For purposes of method assessment and comparison, statistics were used that include percent standard error, bias, standard deviation of differences, in addition to graphic interpretation of residuals. Assessments showed that Stoates model is the most accurate, followed by Schumachers model. They also showed that the linearized Schumachers model reduced accuracy by an average 0.32% and that the relative height method was biased in this study.

VARIAÇÃO DOS MÓDULOS DE ELASTICIDADE E RUPTURA EM MADEIRA DE CEDRO-AUSTRALIANO POR MEIO DE ENSAIOS NÃO DESTRUTIVO E DESTRUTIVO

The elastic of modulus is an important mechanical property in the design of timber structures, so obtaining it through several methods needs to be evaluated. This study aimed to evaluate the use of an efficient technique for determining the apparent longitudinal modulus taking into account the relationship range/height ( L/h ) and the influence of the shear modulus by comparing non-destructive tests with static bending tests. The wood used in paper was Toona ciliata M. Roemer (Australian cedar). Non-destructive tests were performed with the techniques of longitudinal and transverse vibration. It was concluded that the assay of longitudinal vibration is most suitable method to obtain the apparent longitudinal elasticity modulus, because the shear forces that occur due to the shear stresses are not significantly influenced by the variations of the ratio L/h . It was also possible to conclude that the relationship range/height, currently 21 in ABNT’s standards, may be replaced by 20, when determining apparent longitudinal elasticity modules and modulus of rupture, through the static bending and free transverse vibration tests.