Technical efficiency of chain sawmilling in Ogun State, southwest Nigeria

Abstract

Technical efficiency of chain sawmilling in terms of lumber recovery was examined in Ogun State, Nigeria. The data for this purpose were obtained from stump site wood converters otherwise known as artisanal sawyers in the State. Ninety logs from 17 families were sampled for the study. Influence of species density, saw kerfs thickness, log diameter as well as form factor on lumber recovery was examined using multiple and stepwise regression analyses. Result revealed that significant relationship exists between lumber recovery dependent variable and saw kerf thickness, log diameter, Log volume, and species density as independent variables. The study further revealed that Lumber Recovery Factor (LRF) ranges from 23.53% to 67.05% on individual log basis and a mean lumber recovery of 47% for all the sampled logs. Waste partitioning also revealed that the slabs proportion was 28.54% while sawdust and bark were 2.22% and 20.02% respectively. This study has provided a database on the efficiency of this small scale industry. Parameters such as log
diameter, species density, log volume, saw kerfs thickness were found to be useful indices for predicting lumber recovery in artisanal sawing.