Comparisons of Four Methods for Thinning Eucalyptus Hybrid Coppice Shoots in Brazil

Abstract

Both manual and semi-mechanized systems are used for operations involved in coppice remodeling. Thus, there is a paradigm about the higher yield of semi-mechanized operations compared to manual operations. However, the small volume of research on this subject does not present data which is capable of confirming this hypothesis. Thus, the present study aimed to perform a technical analysis of costs, quality and productivity of different methods for conducting regrowth in Eucalyptus grandis x Eucalyptus urophylla hybrid plantations under coppice regeneration in areas of forest fostering. The experiment was conducted under a completely randomized design with four treatments (sprouting methods) and four replications in plots of 360m² each. The methods used were: brushcutter, sickle, machete and hand digger. An F-test (p <0.05) was performed to verify the differentiation between treatments for a given characteristic after verifying the normal distribution of data and homogeneity of variances. The means were compared by analysis of variance at the 5% significance level to analyze if there was significant difference between the operating times in the analyzed methods. An estimate of the costs per hectare was subsequently obtained in each offspring method and the quality of the operation was evaluated by observing the frequency of damage to the remaining trunk. The mean operation time of the methods did not differ significantly (p> 0.05). The brushcutter presented the highest cost per hectare (US$ 40,06/ha-1) and the excavator presented the lowest (US$ 18,65/ha-1). Spreading with the brushcutter presented the lowest percentage of mechanical damage (6.88%) and the sickle obtained the highest (20.63%). It was concluded that the operation with brushcutter was the method that provided the highest productivity, but has the highest operational cost, making the method with brushcutter, advantageous for its low cost, associated with a satisfactory productivity.