Table 1 The softwood-derived forest residues used in the work and their physical characteristics
Source* | Moisture (% wt/wt) ** | Average size(mm×mm×mm) | Notes | |
|---|---|---|---|---|
Lodgepole pine white wood (BKLPP) | Beetle-killed | 7 | 25×25×5 | Disturbance wood. Overall expected to be similar to white wood [26] |
Interface fire slash (IFS) | Williams Lake, some aspen, mostly Douglas-fir and Pine | 28 | 85×50×15 | Juvenile wood contains thinner cell walls, shorter fiber length and higher lignin content [27, 28] |
Logging Residues (LR) | Williams Lake, mostly Lodgepole pine | 42 | 80×25×10 | Contained branches with higher ratio of compression wood. This will likely contribute to higher lignin content when compared to white wood. Will likely have more collapsed cell walls [28, 29] |
Hog fuel I (HOG I) | Olympic peninsula debarking debris, mostly Western Hemlock | 62 | 40×5×2 | Appeared to have a higher bark content. Expected to be challenging to process due to contamination. |
Hog fuel II (HOG II) | Olympic peninsula debarking debris, woody urban waste, Western Hemlock | 58 | 55×10×5 | Primarily woody urban waste, which is extremely variable and may have higher ash content [30] |
BARK | Lodgepole pine, freshly debarked | 33 | 150×30×2 | Reported to be high in extractives, high in lignin, low in carbohydrates, and higher in ash compared to white wood [19, 23] |