Abstract

COELHO JUNIOR, Luiz Moreira; REZENDE, José Luiz Pereira de; CALEGARIO, Natalino  and  SILVA, Márcio Lopes da. Longitudinal analysis of wood charcoal prices in the State of Minas Gerais. Rev. Árvore [online]. 2006, vol.30, n.3, pp. 429-438. ISSN 0100-6762.  http://dx.doi.org/10.1590/S0100-67622006000300013.

Wood charcoal is a renewable energetic resource responsible for the development of the forest key industries in Brazil. The State of Minas Gerais is the largest producer and consumer of charcoal. This study analyzed the longitudinal series of charcoal prices, in the State of Minas Gerais. Average m³ of charcoal prices published by ABRACAVE was used. For analyzing the series, it was used the SARIMA model, in order to find the parameters and to supply better forecasts for charcoal prices. The period from January 1975 to December 2002 was considered to adjust the model and the period from January to December of 2003 for validating the projections of the model. The choice of the most appropriate model was based on graphical analyses, stochastic tests and criteria for evaluation of the model order. Among the studied models, SARIMA (2,0,1,) (0,1,1)₁₂ provided better adjustment and in a economical way. In spite of the appearance of a random factor that distorted the real values of charcoal prices, the projections provided by the model were within the limits of the established significance.

Keywords : Charcoal price; time series; tendency; seasonality; forecast.