Document Type: Original Article
Department of Mechanical Engineering, Obafemi Awolowo University, Ile-Ife
Department of Mechanical Engineering, University of Ibadan, Ibadan
Logging encompasses all activities involved in the processing of fully developed tree for production of finished and intermediate planks of varying sizes. Energy is a major input for logging. In this study energy audit and analysis was used to determine the specific energy and cost of production.
Primary data for the study included site visits and use of questionnaire to collect data on the wood species, energy use pattern and types of equipment used for logging. Measuring instruments such as wattmeter, stop watch and measuring tape were used to measure the current, voltage and power factor; time of operation and size of timber log used in sawmilling in the selected study area
The study covered 24 sawmills spread across 5 states in the south-western part of Nigeria. The study showed that there are seven wood species in the study area. The specific energy (kWh/m3) and average processing costs per unit volume ($/m3) of the seven species measured in the study area are respectively as follows - Afara (Terminalia superba): 1.65 and 0.094; Iroko (Milicia excelsa): 4.48 and 0.260; Mahogany (Khaya ivorensis): 1.47 and 0.084; Opepe (Naulea diderrichii): 1.77 and 0.100; Omo (Cordia millenii): 0.75 and 0.043; Obeche (Triplochyton scleroxylon): 0.58 and 0.033; Igba (Parkia biglobosa): 1.01 and 0.058.
The study showed that the Iroko was the most common wood species processed in the study area and has the highest specific energy for processing. The Iroko was also the most expensive wood specie for log processing in the study area.