- For articles about other types of logging, see data logging or well logging.
Logging is the practice of felling (cutting down) trees, and removing 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.
Operations
A timber harvest consists of the following operations, although not necasarrly in the order given.
- Felling
- 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.
Harvest methods
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.
Logging and forestry
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
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. muha ha ha
Logging and the environment
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.
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 roads
Logging roads are construced 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.
See also
External links
- Hubbard Brook Experimental ForestStudy of logging effects on watersheds
- Landside research Summary of landside studies in clear-cuts
- America's Only National Logging & Forestry Magazine
- Logging Practices: Principles of Timber Harvesting Systems
- Movie of logging in Maine, 1906
- CTL Logging (Enviro-friendly)