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Original Manuscript

Efficiency and productivity of skidder dragging full-trees of Eucalyptus sp.

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Abstract


The development of activities in the forestry sector is constantly evolving. The constant search for improvements in the production system in order to increase production and reduce costs are, therefore, necessary to maintain the growth of forestry. The forest harvesting stage corresponds to a large part of the financial amount spent on the activity and, therefore, it becomes the target of constant studies aiming at its improvement and evolution. The objective of this study is to carry out a technical analysis of the operation of a forest machine skidder operating in the drag of a eucalypts stand in the whole tree system. The technical analysis encompasses factors such as the study of times and movements, operational efficiency and productivity, evaluating the performance of the machinery for three different drag branch distances. In the study of times and movements, the operations “travel without load” and “travel with load” were the operations that demanded the longest total cycle time. The operational efficiency of the machinery approached 90% and the productivity of the skidder decreased according to the increase in the distance from the skidding branch, being in the order of 19.36 m³. hˉ¹ for the 100-meter skid road, 14.01 m³. hˉ¹ for the 200-meter skid road and 8.35 m³. hˉ¹ for the 300-meter skid road.

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Original Manuscript

Hypsometric equation adjustments for multi species clonal plantations of Eucalyptus in the Cerrado Goiano

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Abstract


Eucalyptus forests has an important role in the national economy since the wood generated by this activity supplies most of the forest-based industries and, also, by its contribution to reducing the pressure of exploitation in native forests. In recent years, commercial eucalyptus plantations have expanded to new areas, such as the central regions of Braziland, as a result, there is a lack of multidisciplinary studies on clones adapted to these environments. This way this study aimed to adjust 18 traditional hypsometric models and 2 proposed for a six-year-old eucalyptus multispecies clonal test in the municipality of Catalão, Goiás. For the execution of this work, a total of 80 representative trees were randomly selected to adjusted 20 hypsometric models (arithmetic and logarithmic). To select the best models, the regression significance, the coefficient of determination (R²), the correlation coefficient (r), the standard error of percent estimate (Syx%), and the bias through the root-mean-square error were verified (RMSE) and the graphical analysis of the residuals. Most of the evaluated models presented high values of r and R² and low error and bias rates (RMSE). The adjusted models Hyperbolic (a), Naslund (b) and Prodan (c), DBH²/H =1.8142+0.0997*DBH+0.0261*DBH²; and DBH²/(H − 1.3)=2.2342+0.0870*DBH+0.0274*DBH², were the most appropriate for the estimation of the total height from the diametric data of multispecies clonal plantations in the Cerrado of Goiás, in regions with Cerradão phytophysionomy.

This article is distributed under the terms of the Creative Commons Attribution 4.0 International (CC-BY). Which permits: share, copy and redistribute the material in any medium or format; and adapt, remix, transform, and create from the material for any purpose, even commercial. Once you give proper credit, provide a link to the license and/or indicate if changes have been made. You may do it under any reasonable circumstance, but in no way that suggests that the licensor supports you or your use.

Original Manuscript

Influence of mechanical scarification and single angle germination in seeds of Schizolobium parahyba

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Abstract


The seeds of Guapuruvu inated tegumentary dormancy prevented the entrance of water, consequently, not occurring their germination, next to the aforementioned situation, to the work as having been listed different dormancy techniques in the formation phase of Guapuruvu in the experimental nursery of the Faculty of Social Sciences and Agrárias de Itapeva - FAIT. The new treatments were the scarification techniques for the influence of the seed sowing direction, which can be recognized as the best planting direction and the horizontal water gain as the highest emergence rates, the best treatment for T2 - mechanical scarification Opposite side of the horizontal sowing and sowing with 90% germination. The experimental work was in a completely randomized design (DIC), each day containing 15 seeds with 3 replicates each, the results were submitted to a statistical analysis by the Tukey test at 5% of the probability of error.

This article is distributed under the terms of the Creative Commons Attribution 4.0 International (CC-BY). Which permits: share, copy and redistribute the material in any medium or format; and adapt, remix, transform, and create from the material for any purpose, even commercial. Once you give proper credit, provide a link to the license and/or indicate if changes have been made. You may do it under any reasonable circumstance, but in no way that suggests that the licensor supports you or your use.