FERIC a étudié trois systèmes de récolte en coupe totale afin d'établir des productivités et des coûts spécifiques aux conditions de récolte en forêt mixte. Des systèmes mécanisés par arbres entiers et par bois tronçonnés ainsi qu'un système manuel ont fait l'objet d'observations en forêt mixte et les productivités obtenues ont été comparées aux productivités normalement rencontrées en forêt résineuse. Les trois systèmes ont donné des productivités moins élevées en forêt mixte qu'en forêt résineuse, à volume comparable par tige. Le coût total de récolte, incluant le coût de chargement, était plus élevé q'en forêt résineuse. Le système manuel est celui qui a subi la plus forte hausse de coût. L'abattage, l'ébranchage, le façonnage et le chargement ont été les activités touchées par la hausse de coût, pour un volume par tige et un nombre de tiges à l'hectare comparables. En réalité, le volume moyen par tige en forêt mixte est souvent supérieur à celui en forêt résineuse et le coût moyen de récolte devient alors comparable.
In 1997, FERIC studied a partial cutting operation in the Interior Cedar-Hemlock biogeoclimate zone, on a site west of Kitwanga, B.C. The operation used a Skylead C40 16000 skidder-mounted yarder and Mini-Maki II radio-controlled carriage in a standing skyline configuration and in single-and multi-span applications. The study provided information on productivity and costs for the harvesting system, impact on soil surface conditions, and damage to the residual stand. Productivity functions were derived to predict yarding productivity and costs over a range of operation conditions.
In 1997, FERIC, Alberta Research Council (ARC), Ainsworth Lumber Inc., and Daishowa-Marubeni International Ltd. conducted a study to determine the productivities and costs of various methods of managing logging debris in aspen cutblocks. Conventional roadside processing, two in-block processing treatments (intermediate skid and at-the-stump processing), and roadside processing with subsequent dispersal of slash into the block were assessed.
FERIC studied three harvesting systems in clearcut operations to define their specific productivities and costs under the harvesting conditions typical of mixedwood forest; the systems comprised mechanized full-tree and cut-to-length systems, as well as manual system. FERIC compared their productivities with those typically observed in softwood stands and found that all three systems had lower productivities in mixedwood forest than in softwood forest at comparable stem volumes. The total harvesting cost, including the cost of loading, was higher than in softwood forest, and the manual system showed the greatest cost increase. Felling, delimbing, processing, and loading costs all increased for comparable volumes per stem and numbers of stems per hectare; however, since the average volume per stem is often greater in mixedwood forest than in softwood forest, the actual overall harvesting costs become comparable.
FERIC studied manual and mechanized felling operations with extraction by cable skidder within the Turkey Lakes Watershed in central Ontario. The study compared manual and mechanized clearcutting and partial-cutting operations (shelterwood and selection cuts) and found that felling and extraction productivities were greatest in clearcutting. However, site disturbance depended as much on how the operation was conducted as on the harvesting system used. From the perspective of riparian-zone management, each cut intensity and harvest system offers different advantages with respect to slash distribution and mineral-soil exposure, and their respective merits must be considered in light of the silvicultural objectives.
In order to extend the access for Eastern species to overseas markets and to favour the use of these species in value added products, a better understanding of the lumber machining properties is essential. The objective of this study was to determine the planing, sanding, boring, mortising, shaping, turning and fastening characteristics for the following 14 Eastern Canadian and three overseas species: jack pine, red pine, Eastern white pine, black spruce, white spruce, balsam fir, tamarack, Eastern white cedar, Eastern hemlock, white birch, yellow birch, red maple, sugar maple, trembling aspen, Norway spruce, Scots pine and Japanese sugi. Based on ASTM standards D 1666-87 and D 1761-88 the machining and fastening properties among the 17 species were compared and commented on, with emphasis placed on particular defects of the species. The influence of specific gravity and number of growth rings per inch on the machining and fastening properties was determined by statistical analyses of the data.
Elements of a database on drilling, routing and shaping of particleboard and MDF samples representative for the Canadian industry have were produced. The quality of the surfaces after machining was evaluated subjectively (visually and by touch) and by tracing with a stylus. The density, moisture content, and density profiles of the samples were recorded. The results revealed significant differences in surface quality, both among the particleboard and the MDF samples. The panels were graded according to their performance. Some effects of the panel characteristics on the obtained surface quality were discussed in this report. The methods for surface quality evaluation were compared, and suggestions are made for improvement to the technical evaluation and for further research.
Given the remarkable growth of engineered wood products (EWP) in recent years, and considering industry’s desire to maximise product recovery and value, Forintek undertook a literature search and mill visits to investigate drying practices in Eastern Canada regarding major engineered products (MSR lumber, finger-jointed studs, wood I-joists, glued-laminated beams), and how such practices affect manufacturing processes.
The study revealed that most plants were equipped with on-line moisture detectors to reject undesirable pieces, but, with a few exceptions, little effort was made to adapt drying specifications to EWP requirements. The lumber used was generally dried to the same standards as commodity lumber (19 per cent maximum) even though high moisture contents caused pieces to be downgraded by MSR machines, and moisture content differentials between adjoining pieces was thought to be responsible for some poor finger-joints in structural studs. Based on the experience of some mills, questions were raised as to the effect of high-temperature drying on mechanical properties.
However, attitudes were observed to be changing to a client focus as operations became better established, especially in integrated plants. Recommendations made to support improved returns through drying quality include investigation of 1) the effect of moisture content differentials on finger-joints, 2) optimum moisture contents and drying schedules for MSR production, and 3) the effect of high-temperature drying on I-beam flange material performance.
Green finger jointing is increasingly becoming a proven possibility with three main technological processes, the New Zealand Greenweld process, the US soybean-based adhesive process and the urethane-based adhesive process. This project evaluates only the urethane gluing system by assessing drying degrade and mechanical performance of green-glued finger-jointed material after drying. The New Zealand Greenweld and the US soybean-based adhesive process will be studied in a subsequent investigation.
This study shows that drying degrade in green-glued finger-jointed material is not as serious as first thought. The results also demonstrate that the mechanical properties of this material are in the range of SPS 1 requirements and that green finger-jointing material, such as black spruce and balsam fir, could at least be used to produce stud grade lumber.
L'industrie du sciage est une composante majeure de l'économie canadienne. Avec les coûts croissants d'approvisionnement et la qualité décroissante de la matière première, cette industrie doit améliorer son procédé actuel ou chercher de nouvelles façons de récupérer davantage de chaque arbre. Étant donné que les opérations effectuées lors du procédé de sciage impliquent des décisions comportant plusieurs paramètres, l'utilisation de l'ordinateur s'avère de plus en plus avantageux.
Dans le cadre de ce projet, des modèles ont été développés afin de simuler le sciage selon la courbure. Cette technique, de plus en plus répandue, permet de récupérer davantage de sciages de meilleure qualité. Avec la panoplie d'équipement de sciage courbe ayant chacun ses particularités, il devient difficile de savoir quelle technologie sera la mieux adaptée à nos besoins. L'utilisation de la simulation permettra de mieux comprendre cette technologie et de bénéficier de son plein potentiel.