ResumoEste trabalho teve o objetivo de avaliar o rendimento em madeira serrada e geração de resíduos no desdobro das espécies cedrinho (Erisma uncinatum), cambará (Qualea albiflora) e itaúba (Mezilaurus itauba). Foram desdobradas toras das três espécies em quatro classes diamétricas, variando de 31 a 70 cm de diâmetro, seguindo uma mesma metodologia de desdobro. Foram determinados o rendimento em madeira serrada e o volume de resíduos. O rendimento em madeira serrada não apresentou diferenças estatísticas entre classes diamétricas para as três espécies estudadas. As espécies cedrinho e itaúba apresentaram o maior rendimento na classe diamétrica de 51 a 60 cm. Já a itaúba apresentou a tendência de aumentar o rendimento em madeira serrada com o aumento do diâmetro das toras. A espécie cambará, mesmo não apresentando diferença estatística, foi a que apresentou o melhor rendimento em madeira serrada. A espécie itaúba apresentou menor rendimento e, conseqüentemente, maior geração de resíduos. Toras de maiores diâmetros de cedrinho e itaúba apresentaram defeitos que provocaram a redução no rendimento. Em termos de geração de resíduos, somente a itaúba foi estatisticamente diferente das demais. Palavras-chave: Madeira serrada; rendimento; cedrinho; cambará; itaúba. AbstractYield in sawnwood and quantification of residues for three tropical species. The purpose of this work was to evaluate the yield in sawnwood and the generation of residues from sawing of the following species: cedrinho (Erisma uncinatum), cambará (Qualea albiflora) and itaúba (Mezilaurus itauba). Logs of three species were sawed in four diametric classes, ranging from 31 to 70 cm, using the same sawing methods. The yield in sawnwood as well as the volume of residues were determined. yield in sawnwood didn't show statistic differences between diametrical classes for the three studied species. The cedrinho and itaúba species showed a higher yield in the diametric classes from 51 to 60 cm. On the other hand, itaúba species showed the tendency to increase the yield in sawnwood with the increasing of logs' diameter. Although presenting no statistic differences, the species that showed the better yield in sawnwood was the cambará. The itaúba species presented lesser yield, and so, high generation of residues. The logs of larger diameter of cedrinho and itaúba presented defects that resulted in yield reduction. In terms of the residues' generation, only the itaúba was statistically different from the others species.

Palavras-chave: eucalipto, qualidade da madeira, propriedades tecnológicas. Evaluation of the Main Physical and Mechanical Properties of Eucalyptus benthamii Maiden et Cambage Wood ABSTRACTThe present study aimed to assess the physical and mechanical properties of Eucalyptus benthamii Maiden et Cambage wood. The following physical properties were determined: apparent density at 12 and 0% moisture content, basic density, and indices of contraction. Mechanical properties were determined through tests of static bending, compression parallel to the grain, shear, and hardness in six-year-old wood. Based on the results obtained in the determination of physical properties, E. benthamii wood at the age studied can be classified as moderately heavy and dimensionally unstable. The species showed low resistance with respect to mechanical properties, which can be related to the large amount of juvenile wood observed in the material studied.

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ResumoO objetivo do presente trabalho foi comparar o desdobro convencional e programado de toras de pínus em uma serraria de pequeno porte, tendo sido utilizados modelos de corte para diferentes classes diamétricas aplicadas em um programa de computador MaxiTora, visando a otimização no desdobro de toras. Para tal, foram selecionadas 80 toras de Pinus sp. com diâmetros que variaram de 24 a 33 cm, formando quatro classes diamétricas com 20 toras por classe. Em cada classe diamétrica, as toras foram separadas em dois lotes com 10 unidades, sendo um lote submetido ao desdobro aleatório e o outro lote submetido ao desdobro programado. Para o sistema de desdobro aleatório, os rendimentos obtidos em todas as classes diamétricas variaram de 44,96% a 52,47%, com a média geral correspondendo a 49,01%. No sistema de desdobro programado, os rendimentos obtidos variaram de 49,93% a 55,25% em todas as classes diamétricas estudadas e a média geral correspondeu a 52,14%. A classificação de toras e programação de cortes permitiram aumentar o rendimento da serraria em pelo menos três pontos percentuais. A programação de desdobro de toras resultou em aumento de rendimento em todas as classes diamétricas estudadas. Palavras-chave: Desdobro de toras; rendimento; otimização. AbstractYeld in lumber of Pinus sp. using cutting models in small sawmill. The objective of this research was to compare conventional and programmed cutting of logs pine at small sawmill. The models have been used for cutting different diametrical classes. The software MaxiTora was employed aiming to optimize logs cutting. For such, 80 logs of Pinus sp had been selected with diameters that varied from 24 cm to 33 cm, gathering four diametrical classes with 20 logs each. In each diametrical class, the logs had been separated in two lots of 10 units, then the first lot was submitted to random cutting and the second lot was submitted to programmed cutting. In relation to the random cutting system, the yield obtained in all the diametrical classes varied from 44.96% to 52.47%, and the general average corresponded to 49.01%. In relation to the programmed cutting system, the yield varied from 49.93% to 55.25% in all the diametrical classes studied, and the general average corresponded to 52.14%. Grading of logs and cutting schedule allowed to increase the sawmill efficiency in at least three percentage points. A programming sawing of logs resulted in increased yield in all diameter classes studied. Keywords: Cut of logs; yield; optimization. INTRODUÇÃOO pínus constitui uma das essências florestais mais utilizadas no Brasil na indústria de madeira processada mecanicamente. A região Sul do país concentra a maior parte dessas florestas, sendo os estados do Paraná e de Santa Catarina detentores da maior área plantada com o pínus (Associação Brasileira da Indústria de Madeira Processada Mecanicamente (ABIMCI), 2007).De acordo com Rocha (2002), o rendimento é um dos parâmetros que pode servir de base para os gestores da serraria avaliarem o seu desempenho, por revelar com r...

Evaluation of Yield in Lumber of Eucalyptus for Two Sawing Models in a Portable Sawmill ABSTRACTThe present study aimed to evaluate two sawing models (radial and tangential) for Eucalyptus saligna and Eucalyptus cloeziana in a portable sawmill in order to select which one provides the highest lumber yield. To this end, twenty-four trees with 27 years of age were randomly selected: twelve of each species divided into two diameter classes, 30-34.5 and 35-39.5 cm. The trees were felled and cut in logs of 3.4 meters, and clapboards of 25 mm in nominal thickness were produced. The results obtained showed that, for both diameter classes in both species, the tangential sawing model provided higher yield compared with the radial sawing model. We conclude that lumber of satisfactory quality can be produced under the conditions studied and that these species present good potential to be used as an alternative and safe source of lumber production, being able to substitute some native species from Mozambique.