FERIC compared three harvesting systems (full-tree, tree-length, and cut-to length) on a clay site in northwestern Québec. None of the systems limited rutting to below the acceptable target level; however, cut-to-length harvesting (using a three-machine system) showed slightly better results than the other two systems.
This report represents a breakdown of typical wood harvesting costs in eastern Canada using full-tree and cut-to-length systems. Representative costs were calculated on the basis of harvesting under favorable stand and site conditions, and the resultant costs were allocated to various accounting items (e.g. labor vs machine costs) and to each major work cycle phase. A sensitive analysis based on terrain and tree size variations was also conducted.
Harvesting with 33-m trail spacing was proposed by FERIC as a way to meet the quality criteria for single-tree selection in hardwood forests in Quebec's public forests. The approach is, however, applicable to any partial-cutting treatment in hardwood forests, and the method was studied in 16 operations in 2003-2004. The approach represents an acceptable compromise between protection of the residual stand and operating costs, as the productivity of the feller-bunchers using this method decreased only slightly as a result of increased travel. The operations that FERIC studied did not all meet the target quality criteria, but provided an adequate level of protection of residual stems. The method requires a certain degree of control to limit the felling of non-marked stems, and the use of evaluation criteria specially adapted to this method would facilitate its implementation.
Researchers at the Canadian Forest Service (CFS) are conducting studies to protect trees against certain pests from here and abroad. Some of the most well-known are the emerald ash borer and butternut canker. Their goal is to maintain the benefits associated with trees and biodiversity.
Des chercheurs du Service canadien des forêts (SCF) effectuent des études visant la protection des arbres contre certains ravageurs venus d’ici ou d’ailleurs. Parmi les plus connus, mentionnons l’agrile du frêne et le chancre du noyer cendré. Leur but : maintenir les bienfaits associés aux arbres et la biodiversité.
Les auteurs définissent la qualité du bois en fonction de ses emplois, puis décrivent l'anatomie et la croissance du bois en regard de ses caractéristiques microscopiques et macroscopiques telles qu'observées en coupe transversale. Les exigences liées aux emplois sont énoncées selon les différentes classes de bois. Diverses caractéristiques déterminant la qualité du bois sont présentées et leurs conséquences pratiques pour la transformation du bois et les produits sont expliquées. Ces caractéristiques sont: la densité du bois, les variations de la densité, la répartition des bois juvénile et adulte, la proportion de duramen et d'aubier, la longueur des fibres, l'orientation des microfibrilles, le bois de compression, les noeuds, le grain ou la texture, le fil et les substances extractibles. Enfin, les auteurs traitent de la possibilité de modifier les paramètres de croissance de l'arbre et la qualité du bois grâce à un contrôle de la densité du peuplement. Les forestiers sont invités à prendre en considération les répercussions des travaux sylvicoles propres à chaque station.
The major defining characteristic of lumber cut from trees that have been infected with the mountain pine beetle is the extent of fungal bluestain in the sapwood. Forintek Canada Corp. scientists have previously observed that bluestained wood appears to have different dimensional stability characteristics than non-stained wood when subjected to repeated wetting and drying. Bluestained wood has also been reported to show increased permeability, which may make treatment with liquids such as wood preservatives easier. However, no data is available on how bluestained wood resulting from the beetle attack might affect. We therefore identified the need to generate data on the dimensional stability, checking, and permeability characteristics of bluestained wood compared with non-stained wood.
To examine dimensional stability, specimens of bluestained and non-stained 2 x 4 in. lumber were subjected to wetting/drying cycles. After 5 and 10 cycles, the amount of bow, crook, cupping, twist, and checking was measured. The permeability of the wood was also determined by weighing end-matched specimens before and after a 1-, 4-, and 24-hour dip or after a pressure treatment cycle with chromated copper arsenate preservative, and then calculating the uptake and preservative retention.
The results clearly show that when repeatedly wetted and dried, such as occurs in exterior end uses, bluestained beetle-killed wood is more dimensionally stable (less cupping and twist) and checks less than non-stained sapwood, but is more permeable to water. The stresses appear to be relieved by many micro-checks rather than fewer large checks. Overall, the improved dimensional stability should result in the lumber made from stained wood remaining straighter.
Increased permeability of the bluestained wood was confirmed by data showing enhanced chromated copper arsenate (CCA) uptake and penetration. One implication of the stained sapwood treating more readily than non-stained wood is that in batches of preservative-treated wood, the stained wood is liable to be overtreated or the non-stained wood undertreated. As anticipated, bluestain in the sapwood had no effect on the penetration of preservative into the heartwood, the most refractory part of the wood. Treatment with CCA also masked the bluestain by coloring it green.
The increased permeability probably also has implications for ease of air or kiln drying and possibly reduced degrade in the kiln.
Insects - Attack on trees
Stains - Fungal
Pinus contorta Dougl. var. latifolia - Defects
Preservatives - Permeability
Preservatives - Penetration
Pinus contorta Dougl. var. latifolia - Preservation