Logging Residue from the Tropical High Forests in the Western Region of Ghana

Abstract

Eshun, A. A. 2000. Logging residue from the tropical high forests in the Western Region of Ghana. 161 pp. M.Sc.F. thesis, Faculty of Forestry and the Forest Environment, Lakehead University, Thunder Bay, Ontario, Canada. Major Advisor: Dr. H. Gary Murchison. Key words: Western Region of Ghana, logging residue, volume estimation, harvesting efficiencies, sample size, biomass equations, volume equations, residue utilization. In the face of increasing demand for industrial wood and the serious reduction of the forest resource base in Ghana, logging is reported to be wasteful. However, the level of wastage or residue generation has not been well quantified and described in regard to its potential uses and/or effects on the resource base. Data were collected from 100 sample trees during normal commercial harvesting operations in five logging sites within four forest districts in the Western Region of Ghana. The data were analysed in order to assess the extent of logging residue. On average, 79 percent of the total bole volume and 68 percent of the measured above-ground total tree volume was extracted as logs. Thus, 32 percent of the measured above-ground total tree volume was left in the forest as residue. Branch wood was the highest average proportion of logging residue followed by crown-end offcuts, butt-end offcuts and stump wood. Logging residue may be attributed to a variety of causes including natural defects, and human errors and/or inefficiencies of machine operators. This study indicated significant differences in harvesting efficiencies among timber species and among logging companies. Efficiencies were highest in the two large-scale companies followed by the mediumscale and the small-scale companies. These differences emanated from the level of integration of the companies, equipment and machinery available, the competence of the workforce, terrain conditions, bole shape and form, bole length, occurrence and extent of natural defects, and rarity and commercial value of the species. The study further showed that for a combination of various species, 56 sample trees will be required at an allowable error of }10 percent and a confidence level of 95 percent in order to estimate the proportions of the various identified logging residue (or tree sections). Provisional biomass models were developed for predicting the measured above-ground total tree volume and thereby the measured above-ground total residue volume. Also, provisional local and standard volume equations were developed for forest resource management. Generally, the species-specific models were more precise than the generalised equations. In order to increase recovery and utilization of harvested trees, potential types of forest products which might be converted from logging residue were identified. These products include small-size solid products (e.g., scantlings, strips, squares, narrows, shorts, parquet and strip floorings, broomsticks, profile boards, mirror and picture frames), chips for wood-based panel products, pulp and paper, charcoal, fuelwood and other potential commercial uses.