log

1 a segment of the trunk of a tree when stripped of branches

2 large log at the back of a hearth fire [syn: backlog]

3 the exponent required to produce a given number [syn: logarithm]

4 a written record of messages sent or received; "they kept a log of all transmission by the radio station"; "an email log"

5 a written record of events on a voyage (of a ship or plane)

6 measuring instrument that consists of a float that trails from a ship by a knotted line in order to measure the ship's speed through the water

1 enter into a log, as on ships and planes

2 cut lumber, as in woods and forests [syn: lumber] [also: logging, logged]logging n : the work of cutting down trees for timberlogging See log

English

Pronunciation

• Rhymes: -ɒɡɪŋ

Verb form

logging

1. present participle of log

Logging is the process in which trees are cut down for forest management and timber. Logging is controversial due to its potential environmental and aesthetic impacts.

Use of the term logging in forestry

In forestry the term logging is sometimes used in a narrow sense concerning the logistics of moving wood from the stump to somewhere outside the forest, usually a mill. In common usage however the term may be used generally to mean a range of forestry or silviculture activities. For example the practice of the removal of a valuable trees from the forest has been called selective logging sometimes confused with selection cut. Illegal logging refers to what in forestry might be called timber theft. An example of illegal logging is cedar theft, which is most common in the American Pacific Northwest. Timber theft in all forms is quite rare in the United States. In common usage what is sometimes called clearcut logging is not is necessarily considered a type of logging but a harvest or silviculture method and is simply called clearcutting or block cutting. In the forest products industry logging companies may be referred as logging contractors.

Logging usually refers to above-ground forestry logging. Submerged forests exist on land that has been flooded to create artificial dams and reservoirs, and trees have started to be felled there too (see underwater logging).

Logging and forestry

The two main stakeholders in most logging operations are the landowner and the logging contractor. Prior to a large harvest a landowner will often hire a consulting forester. Owners of large industrial tracts may employ their own foresters. During planning for the harvest the forester will determine how best to meet the landowner's objectives, including the silvicultural system to be used, even-aged or uneven-aged management, layout of roads and landings. If a selection cut is planned the forester will mark the trees intended to be cut or if a clear cut which blocks are to be harvested. A well-managed forest will be harvested according to a forest management plan. This plan should include areas off-limits to cutting such as sensitive habitat, vernal pools and riparian zones.

A logging contractor may get paid according to the volume of wood harvested. There are over 320,000 jobs that have to do with the logging industry in Canada.

Logging methods

The above operations can be carried out by different methods, of which the following three are considered industrial methods: :Trees are felled and 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 (and the nutrients it contains) in the cut area where it must be further treated if wildland fires are of concern.

Full-tree logging

Trees are felled and transported to the roadside with top and limbs intact. The trees are then delimbed, topped, and bucked at the landing. This method requires that slash be treated at the landing. In areas with access to cogeneration facilities, the slash can be chipped and used for the production of clean electricity or heat. Full-tree harvesting also refers to utilization of the entire tree including branches and tops. This technique removes both nutrients and soil cover from the site and so can be harmful to the long term health of the area if no further action is taken, however, depending on the species, many of the limbs are often broken off in handling so the end result may not be as different from tree-length logging as it might seem.

Big 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 is a dangerous occupation. In the United States, it has consistently been one of the most hazardous industries, having a fatality rate over 21 times higher than the rate for all workers in the US. Loggers work with heavy, moving weights and the use of tools such as chainsaws and heavy equipment on uneven and sometimes unstable terrain. Loggers also deal with severe environmental conditions such as inclement weather and severe heat or cold. An injured logger is often far from professional emergency treatment.

Traditionally, the cry of "Timber!" developed as a warning alert fellow workers in an area that a tree is being felled, so they should be alert to avoid being struck. The term "widowmaker" for timber that is neither standing nor fallen to the ground demonstrates another emphasis on situational awareness as a safety principle.

The risks experienced in logging operations can be somewhat reduced, where conditions permit, by the use of mechanical tree harvesters and forwarders.

Logging and the environment

The many impacts of logging on the environment can be divided into two broad categories, the timber harvest itself, that is, the removal of trees from the forest, and secondly the impact caused by logging operations such as falling or dragging trees and operation of machinery in the forest.

Impact of tree harvesting

Removal of trees alters species composition, the structure of the forest, and can cause nutrient depletion. This may provide opportunities for some species while creating a loss of opportunity for others. Trees providing midday shade to streams which may alter the stream's temperature either by preventing the sun from shining on the water by day, or by preventing the water from radiating the heat back at night. In altering the balance of animal and plant species, logging, if not limited to sufficiently small areas, alters the ecological system of the forest. The effect on ecosystems and on biodiversity is the small-scale effect of unrestricted logging.

The large-scale effect of the removal of trees is obviously the impact on the level of carbon in the atmosphere, with its consequences on global climate. Besides the carbon release due to possible burning associated with logging, or possibly with wood processing, the removal of trees prevents carbon from being captured by the trees from the atmosphere. Deforestation, frequently associated with logging, has been assessed to be in fact responsible for 17 percent of annual global carbon a level higher than the one from emissions due to transportation.

Impact of logging operations

Modern ground based logging operations require the use of heavy machinery in the forest. In some areas roads must be built which often causes habitat fragmentation and increased edge effect. The use of heavy machinery in a forest can cause soil compaction. Harvesting on steep slopes can lead to soil erosion, landslides, and water turbidity. Logging on saturated soils can cause ruts and change drainage patterns. Harvest activity near wetlands or vernal pools can degrade the habitat. Forest machines use oils which, if not handled carefully, can cause pollution. Roadbuilding for access to timber in frontier forests often opens up areas previously not accessible, which facilitates further development such as farming.

Mitigation

These problems can be mitigated by using low-impact logging and best management practices, which set standards for reducing erosion from roads. Damage to streams and lakes can be reduced by not harvesting riparian strips. Mitigating the effect of logging can require the full restriction on logging on ecologically important lands, such as forests with a high level of biodiversity. Technological advances in logging equipment can reduce ruts and soil disturbance. Processors and forwarders with caterpillar tracks or other designs to lower ground pressure help to reduce machine impact .

Benefits

Some claim logging has positive effects on the environment (though all are anthropocentric ecological inputs)

1. removing damaged or diseased trees or both, and
2. opening up the canopy to promote growth of smaller, healthier trees. Branches, snags, 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 browsing mammals.
3. Select cutting can improve the forest and bring to market trees that would otherwise decompose.
4. In the 19th and early 20th century, logged over areas were sometimes sold or donated to the state, or forfeited for back taxes. Following the maturation of new growth, usually of different tree species, the reclaimed land became the basis of certain outstanding recreation areas, including the White Mountain National Forest.

See also

• Sawmill
• Chain saw
• Log scaler
• Log bucking
• Cable logging
• Illegal logging
• Logging wheels
• Shovel logging
• Skyline logging
• Salvage logging
• Underwater logging
• Lumberjack World Championships In Canada

References

External links

• National Institute for Occupational Safety and Health - Logging Safety Page
• http://www.fs.fed.us/r9/forests/white_mountain/about/history/index.php

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