Time filter

Source Type

Teo S.J.,UNOESC | Bianchi J.C.,Academico de Engineering Florestal | Peloso A.,Academico de Engineering Florestal | Nava P.R.,Academico de Engineering Florestal | And 3 more authors.
Floresta | Year: 2012

This research aims to analyze probability of density functions (pdf) Normal, Ln-Normal, Johnson Sb, 3PWeibull, Gamma, Beta and Weber in order to describe diameter changes in Pinus taeda L. plantations structure, in the region of Caçador - SC, Brazil, at different age and site classes. The data processing was carried out by Solver tool of the software MSExcel2010, using the linear algorithm of generalized reduced gradient (GRG) for interaction of parameters. As result, Johnson Sb and 3PWeibull presented the best performances. For the pdf adherence evaluation, it was recommended the employment of R2,R2 ad,syx e syx% statistics, besides the Kolmogorov-Smirnov test, in any situation, specially, when there is more than 5,000 observations. Generally, there was an increasing in the range of diameter values and a flatness of diameter distribution at advancing age and improvement of the site productivity. At age advancing, there was an increasing of maximum diameter and modal diameter values of distributions, for the higher productivity site classes, on the other hand, the same did not occur for the low productivity site class.

This study aimed to test different statistical models for fitting site index curves and check if the anamorphic curves generated were satisfactory to classify the loblolly pine (Pinus taeda L.) plantations in the region of Caçador, Santa Catarina State, Brazil. The data of dominant height (hdom) used in this study were obtained from permanent plots of fixed area and rectangular shape, with areas of 500 and 625 square meters. The plots were distributed randomly in the stands to cover the largest possible variability of productivity. The selection of the best equation was made by the following fitting and precision statistics: adjusted coefficient of determination (R2 aj), standard error of estimation (Syx), standard error of estimate in percentage (Syx%) and graphical distribution of the residuals in percentage. The monomolecular model showed the best performance, so it was chosen for the construction of the site index curves by guide curve method. After construction of the site index curves, the stability of the curves was also tested, which indicated the anamorphic pattern of the curves generated by the equation for site classification of loblolly pine plantations in the region of Caçador, Santa Catarina State, Brazil.

Lopes E.S.,UNICENTRO | Oliveira F.M.,UNICENTRO | Malinovski J.R.,Federal University of Paraná | da Silva R.H.,Academico de Engineering Florestal
Floresta | Year: 2013

This research aimed to execute biomechanical evaluation of workers at pruning activities in Pinus taeda L. plantations, in order to improve comfort, safety and health conditions. The data were collected at a forest service company, located in the Pioneer Northern, Paraná State, Brazil; it was focused first, second and third pruning activities by manual and semimechanized methods. In order to improve biomechanical evaluation, workers were filmed during their activities and the data submitted to the OWAS (Working Postures Analysing System) and 3DSSPP (Prediction of Static Force Posture 3D) programs. Results revealed that postures adopted by workers were considered normal, with no necessary corrective ergonomic actions. In some moments posture adopted by workers, arms extended above their shoulder level in the manual pruning, pointed to a necessary adjust of cable pruning saw, in order to avoid future health problems. There wasńt compression on L5-S1 column disc, however, it was identified that higher stress is caused by manual method as increase the pruning height. The hip was the articulation most affected, but not causing damage to workers' health.

Lopes E.D.S.,UNICENTRO | Sampietro J.A.,Mestrando em Ciencias Florestais | Pereira A.L.N.,Mestrando em Ciencias Florestais | Oliveira D.,Academico de Engineering Florestal
Floresta | Year: 2011

The process of mechanization of timber harvesting allowed a significant increase in productivity and quality of operations. However, heavy traffic of large machines has been largely responsible for soil compaction in forest areas. This research aimed to evaluate the latosol compaction caused by skidder with tires and tracks over the tires. The study was developed in the logging areas of a forestry company located in Parana State. Soil compaction was evaluated by soil bulk density, aeration porosity, total porosity and penetrometer resistance. The soil samples and date of penetrometer resistance were taken at four points equally spaced along both the trails with and without traffic at three depth levels (0 to 15, 15 to 30 and 30 to 50 cm). The results showed that the skidder equipped with tires was responsible for the greatest change in density, with 1.22 and 1.17 mg.m-3 in the depth of 0 to 15 and 15 to 30 cm, respectively. There was not significant change in soil physical properties caused by skidder traffic with the different wheeled types, proving that the installation of the tracks over tires did not result in smaller soil compaction.

Loading Academico de Engineering Florestal collaborators
Loading Academico de Engineering Florestal collaborators