Logging
For articles about other types of logging, see data logging or well logging.Logging is the process in which
lumberjacks fell (cut down)
trees, and remove them from the
forest. It can be part of on-going
forest management or to convert forests to
other uses.
Most conventional logging is either for
pulpwood production for the manufacture of
paper products or for sawlogs for
lumber production. A significant amount of logging is also done for
firewood production, and, today, a very large and growing amount of logging is being done for
chipwood production.
A timber harvest consists of the following operations, although not necesarrily in the order given.
;Felling the shank:The standing tree is cut down or 'felled' by
chainsaw or
harvester or
feller buncher.
;Processing :The tree is turned into logs by removing the limbs (
delimbing) and cutting it into logs of optimal length (
bucking).
;Primary transport :The felled tree or logs are moved from the stump to the landing. Ground vehicles can
pull,
carry, or
shovel the logs.
Cable systems can pull logs to the landing. Logs can also be flown to the landing by
helicopter.
;Secondary transport:The logs are transported to the mill, commonly by truck but in the past this has included
train,
driving logs downstream, or pulled as a floating
log raft.
The above operations can be carried out by three different methods:
Tree-length :Trees are felled then delimbed and topped at the stump. The log is then transported to the landing, where it is bucked and loaded on a truck. This leaves the slash in the cut area.
;Full tree :Trees are felled and transported roadside with top and limbs intact. The trees are then delimbed and bucked at the landing. This method can leave large piles of slash near the road. Full tree harvesting also refers to utilization of the entire tree including branches and tops.
;
Cut-to-length:Trees are felled, delimbed, bucked, and sorted (pulpwood, sawlog, etc.) at the stump area leaving limbs and tops in the forest.
Harvesters fell the tree,
delimb and
buck it, and place the resulting logs in bunks to be brought to the landing by the
forwarder.
Managing a forest is the subject of
Forestry. A well managed forest will be harvested according to a
forest management plan. This management plan would include the
silvicultural system to be used, even-aged or uneven-aged management, layout of roads and in the case of a selection cut, marking of tree intended to be cut. Harvesting timber can also be done without regard to damage done to the forest or future productivity. This sometime is called cut and run logging.
Clearcut and select cut
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Clearcuts in the Canadian Rockies taken from "Green Spirit: Trees are the Answer." |
Clearcutting is a practice in which all, or nearly all, trees in a selected area are harvested in a logging operation. There is no agreed upon minimum area of a clear cut, but areas smaller than 5 acres in size would typically be considered
patch cuts.
A selection harvest removes specific trees while leaving others. A selection cut can remove mature timber or
thinning to improve the timber stand.
Logging can impact the environment both by cutting down trees and by the disturbance caused by moving it to the landing. Removal of trees alters species composition and the structure of forest and can cause
nutrient depletion. Harvesting in high value ecologically sensitive lands can lead to
habitat loss. Machines used in logging often disturbs the
soil. The use of heavy machinery in the forest can cause
soil compaction. Harvesting on steep slopes can lead to
erosion and
mudslides. Logging on saturated soils can cause ruts, and change drainage patterns. Harvest activity near
wetlands or
vernal pools can degrade habitat. Loss of trees adjacent to streams can increase water temperatures. Harvesting adjacent to streams can increase
sedimentation in streams lowering water quality.
Colonization of the forest area by
invasive exotics is a problem with poorly operated forestry practices, especially in the eastern North American
hardwood forests. Some of the most marked effects of large-scale clearcutting, including the stream corridors, has been seen in the American
Pacific Northwest, where
salmon spawning and rearing
habitat has been damaged.
|
Regeneration on a 15 year old clearcut |
These problems can be mitigated by using
best management practices, which set standards for reducing erosion from
roads. Damage to streams and lakes can be reduced by not harvesting
riparian strips. Ecologically important lands are often set aside as reserves.
The logging industry is often
portrayed in the
media and
popular culture as one of the most ecologically destructive corporate practices on earth. However, logging companies contend that despite some notable cases of severe environmental degradation,
agriculture,
livestock grazing, mineral
mining, the
petroleum industry and
urban sprawl are even greater contributors to deforestation and ecological degradation. As an example, they cite that a house built out of
steel,
plastic and
concrete have higher
life-cycle cost and requires more energy and non-renewable resources to produce than a house built with wood products.
Logging can also have positive effects on the environment by removing damaged/diseased trees and opening up the canopy to promote growth of smaller healthier trees. Branches and other non marketable parts of the tree provide shelter for
wildlife. Underbrush that would not otherwise grow due to lack of sunlight thrives and is an important food source for deer and moose. Select cutting can improve the forest and bring to market trees that would otherwise decompose. New advances in logging equipment are reducing ruts and soil disturbance.
Processors and
Forwarders with walking "legs" supported by wide pads distribute the weight of the machine and reduce
soil compaction.
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Truck load of ponderosa pine, Malheur National Forest, Oregon, USA, 1942 |
Logging roads are constructed to provide access to the forest for logging and other forest management operations. These are commonly narrow and unpaved. Logging trucks, which, when loaded, can carry up to 4,500 kg of wood are generally given right of way.
Construction of these roads, especially on steep slopes, can increase the risk of
erosion and
landslides which can increase downstream
sedimentation.
Logging roads are often the major source of sediment from logging operations, which can continues long after operations are completed in the area. The decommissioning of these roads involves the restoring of natural habitat, which can be quite expensive, usually as much as it originally cost to construct the road.
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Forestry*
Clearcutting*
Cut-to-length logging*
Cable Logging*
Log driving*
Deforestation*
Old growth*
Illegal logging*
Logging roads*
University of Washington Libraries Digital Collections â€" Darius Kinsey Photographs Images from the period 1890-1939, documenting the logging industry in Washington State. Includes images of loggers and logging camps, skid roads, donkey engines, loading operations, logging trucks and railroads.
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University of Washington Libraries Digital Collections â€" Clark Kinsey Photographs Over 1000 images by commercial photographer Clark Kinsey documenting the logging and milling camps and other forest related activities in Washington State, ca. 1910-1945.
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University of Washington Libraries Digital Collections â€" Industry and Occupations Photographs An ongoing and expanding collection devoted to the workers in the Pacific Northwest from 1880s-1940s. Many occupations and industries are represented including the logging and lumber industry.
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Hubbard Brook Experimental ForestStudy of logging effects on watersheds
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Landside research Summary of landside studies in clear-cuts
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America's Only National Logging & Forestry Magazine*
Logging Practices: Principles of Timber Harvesting Systems*
Movie of logging in Maine, 1906*
CTL Logging (Enviro-friendly)
