Aspectos operacionais e custos de dois sistemas de exploração de lenha na caatinga

Abstract

Sustainable forest management in the Caatinga has great importance, especially to meet the main demand of energy inputs used in the Northeast. However, there are few studies to support the planning and the technical and economic design of firewood logging activities in Caatinga. In this context, this study aimed to analyze and estimate the costs of two logging systems, one manual (with ax and sickle), located in the municipality of João Câmara, Agreste Region, and other semi-mechanized (with chainsaw), located in the municipality of Santa Cruz, Agreste Region, in areas with Sustainable Forest Management in the state of Rio Grande do Norte, Brazil. Data collection was based on observation and timing of operating activities (time and motion study). They were considered effective work the following activities: cutting of trees (felling and bucking), piling, firewood organization, and opening truck trail. On average, the total working journey was 10.17 hours in the manual system, with operational efficiency of 60.5%, and 7.22 hours in semi-mechanized system with operational efficiency of 67.2%. The average productivity was higher in semi-mechanized system, 6.4 stereos per man per day, or the equivalent of 1.32 stereos per effective hour. In manual system, were produced, on average, 4.8 stereos per man per day, and equivalent to 0.78 stereos per effective hour. The cost of the manual operating system was R$ 11.17 per stereo (R$ 8.71/h) while the semi-mechanized system was R$ 14.44 per stereo (R$ 19.06/h). The cost of the transport related to the manual system was R$ 5.47 per stereo for the average distance of 75 Km. Regarding to the semi-mechanized system, the cost was lower (R$ 2.54 per stereo) due to the shorter distance transported (20 Km). Logging was the principal component of the total cost of firewood, representing 66% in the manual system and 83% in semi-mechanized system.