FROM LOG TO LUMBER
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etween the standing tree and the boards you pick off the rack at the lumberyard stands a complex process that requires many people to apply enormous skill at every step. Undetected defects in the standing tree, damage
caused during felling, poor judgment in bucking or inattentive sawing at the mill can sabotage the value of a tree and raise the sawmill’s—and the woodbuying consumer’s—costs. Although power saws have replaced muscle-driven
pit saws in the forest and at the mill, and cuts are now guided by laser beams and computer technology instead of chalk lines, no replacement has been devised for the practiced eye of an experienced lumberman.
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A tree’s journey to the lumberyard begins in the woods, when a forester or timber cruiser evaluates the trees for cutting. Not all cut trees will be earmarked for the saw mill; some will be used for pulp or firewood. These lower-grade trees are deliberately harvested to give the residual stock better access to nutrients and more room to grow, thus increasing the timber stand’s value. The very best trees will be reserved for veneer.
Since most of the highest-grade lumber will come from the area just under the bark, the forester must be able to detect at a glance clues that betray defects
in this area. Knots, for example, can be particularly troublesome, depending on where they are located. In the bottom part of the tree, where they are usually indicated by a slight disfiguration of the bark, knots may be so deeply overgrown that they will not affect the value of the outer wood. But further up, where they are typically indicated by concentric circles or even bumps in the bark, knots pose more serious problems in terms of quality.
The ability to distinguish between different types of fungi is another important skill in tree evaluation. All fungi cause some damage, but certain species
are rapacious: In beech and hard maple, for example, a single body of false tinder fungus on the outside of a tree may signal the presence of a 12- to 14-foot-long column of decay within. If the decay were confined to the center of the tree, this would be less of a problem, but many fungi infest the most valuable outer wood. Any scarring of the bark is thus suspicious, since even the tiniest opening makes a tree susceptible to fungal infection.
Bird damage—specifically peckholes made by the yellow-bellied sapsucker— also affects a tree’s commercial value. Unlike its woodpecker cousins, which
eat wood-boring insects that infest dead wood, the yellow-bellied sapsucker feasts on the sap, wood cells, and inner bark of live trees. Persistent feeding results in long streaks of stain that effectively render the wood worthless.
Trees are cut with three passes of a chain saw. The first two cuts remove a wedge about one-third of the diameter of the tree, facing the intended direction of fall. The tree is felled by the third cut, or backcut, made opposite to and a few inches above the wedge. As the tree falls, its direction is controlled by a “hinge”
of wood between the wedge and back - cut. Expert fellers consider many factors before making the cuts—the condition of the felling site, wind direction, the lean of the tree, and the presence of dead branches in adjacent trees, aptly called “widowmakers.”
Once the limbs have been removed, the tree is skidded to a staging area, or landing, where it is bucked into logs. To ensure that the wood is cut to the highest possible grade, the bucker—like the forester or tree cruiser beforehand—has to “read” the tree for signs of defects before setting to work. Bulges in the bark indicate knots that are close to the sur
face; large-diameter rotting branches point to decay within the tree trunk. While the optimal length for hardwood logs is 16 feet (8 feet for veneer-quality logs), cutting logs to this length is not always possible. Sometimes the bucker cuts 8-foot and 12-foot logs to avoid defects that would render a larger log worthless.
In some parts of North America, especially the Pacific Northwest where trees are exceptionally large, bucking is done at the felling site before the logs are transported to a central yard. Steeply sloping
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terrain may require the logs to be gathered in from the forest floor using a series of cables. One such system is known as high-lead logging. Two main cables— one called a haulback and the other a mainline—are rigged to the top of a tall mast. Several other cables, called chokers, dangle from the mainline. Trees are felled so they land with their butt sections pointing uphill; crewmen wrap each choker around the butt section of a bucked-up log, signal the head operator, and the logs are reeled up the hill to the central pile, usually located next to a lumber road. When the logs have been detached, the haulback cable is used to pull the mainline and its chokers for another load. No matter how they are moved from the felling site or when they
are bucked, logs are loaded onto trucks with a hydraulic grapple hook for the trip to the sawmill.
