Volume 3, numéro 1, july 1991

EN :

An analysis is made of the energy inputs in the production of copper in Falun, Sweden, in the mid 17th century. This mine produced at that time more than half of the world production of copper. The dominant role of the forests is identified and the contribution to Sweden's wealth and security described, enabling Sweden to develop to the most powerful nation in Northern Europe during the period 1560-1720.

EN :

A 1/11 scale model of a walking machine with five legs was constructed, and its operation as a feller-buncher investigated. As slopes steepen, the machine when positioned straight up the slope becomes more efficient than when positioned parallel to the contour lines, because the downward operational range of the machine decreases with increased slopes. In the experiments, the ground pressure of the legs on the end opposite the boom was nearly zero when the boom holding felled trees was positioned at the side of the body and extended farthest from the body. However, further investigations (including such factors as ground disturbance, the operation of the machine, the degrees and the length of slope, and the fuel consumption) of felling operations are needed. Feller-bunching tends to be less efficient as tree density increases assuming that felling time per tree remains constant as tree diameter changes. To obtain greater productivity with the machine as a feller-buncher, it is essential to achieve faster walking-time and shorter felling-time per tree.

EN :

The structural behaviour and performance of nailed plywood gusset knee joints of timber portal frames are investigated. An analytical study has shown, and experimental study has confirmed, that the behaviour of the joints in terms of strength and stiffness, distribution of stresses, and rotation of nail groups within the gusset haunches, is directly related to the joint's component arrangements, plywood grain orientation and the dowel action of the nails.

An empirical method is presented which permits calculation of the short-term ultimate strength of plywood gusset plates, for various component arrangements of the knee joints, based on the strain distribution along the critical section of the haunched gussets. It is shown that a considerable gain in ultimate strength and performance can be achieved if a correct joint configuration is used.

EN :

The use of small instead of large stumps for cable logging anchors will usually result in applied loads approaching the load capacity of the anchors more closely. The use of small stump anchors is then contingent on better means of assessing their capacity. The results of field load tests of Douglas-fir and western hemlock stump anchors are reported. Ultimate loads were modeled as power functions of DBH. In addition, the relation between load and movement relationships for the stumps are modeled using a hyperbolic function that also provides an estimate of ultimate load. Practical use of the model equations requires knowledge of failure statistics and the acceptance of a probabilistic anchor capacity. Probability is applied to the re-rigging required when an anchor fails to perform adequately and to total pull-out failure.

EN :

This paper evaluates the issues associated with the computer integration of the various technologies now available to hardwood log sawmills, so that these technologies will cooperate in helping the sawmill achieve better lumber yield. The concept of computer integration, and the current sawmill setup, are reviewed. A model of a computer-integrated hardwood sawmill is described. Issues concerning the integration of both hardware and software are also discussed.