Quality assessment of cut-to-length logging residues for bioenergy production in Northwestern Ontario

Abstract

The use of the cut-to-length (CTL) forest harvesting method has been increasing in eastern Canada due to its versatility and its potential for lower environmental impact. In this study we assess the quality of CTL logging residues for bioenergy production in Northwestern Ontario. The qualities assessed were moisture content, gross calorific value, and ash content. Analysis of variance was used to determine whether duration of storage, logging residues species class, or diameter class had a significant effect on each of these qualities. Moisture content values ranged from 10.6% to 28.9% green-weight basis. Drying seasons, logging residues species class, and diameter class all had a significant effect on moisture content. The gross calorific values of residues ranged from 19.5 to 22.8 MJ/kg. Drying seasons and species class did not have a significant effect on gross calorific value, while the diameter class of logging residues did. The ash content of the CTL logging residues ranged from 0.4% to 4.2%. Ash content showed a decreasing trend with increase in number of drying seasons. Drying seasons and diameter class had a significant effect on ash content, but species class did not show any significance. CTL logging residues left in the forest continued to increase in quality from 1 to 3 drying seasons after harvest. From the transportation and combustion viewpoints, moisture content is reduced to an acceptable level after one drying season.