Sunday, November 25, 2007
Disambiguation: other uses of the term Logging
Logging is the process in which trees are sawed down usually as part of a timber harvest. Timber is harvested to supply raw material for the wood products industry including logs for sawmills and pulp wood for the pulp and paper industry. Logging can also remove wood for forest management goals. Logging is controversial due to its perceived environmental and aesthetic impacts. Well planned and well managed logging operations often have very low impact on the environment.
Use of the term logging in 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.
A timber harvest can consist of the following operations, although not necessarily in the following order.
Planning - Identifying optimal timing, access, and layout of harvest.
Permitting - Regulatory review can include public notification, environmental assessment, taxes, and fees.
Sale - Many timberland owners employ their own loggers, while others hire or sell the right to log to a logging company.
Accessing - Logging roads, logging camps, and weighing stations are built or repaired as needed.
Marking - The area or individual trees to be harvested are clearly identified.
Measuring - Assessing the volume of timber that will be produced by the harvest.
Marketing - Arranging supply contracts with timber customers, this may be undertaken through competitive sale methods or as part of a negotiation with preferred customers.
Felling - The standing tree is cut down or felled by chainsaw, 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).
Stump to landing - 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.
Landing to mill - The logs are commonly transported to the mill or port by truck, but in the past, this has been done by train, by driving the logs downstream, or by pulling them as a floating log raft.
Burning - Burning logging debris and other woody material on the site can reduce future fire risk and release nutrients.
Herbicide - Eliminating competing seedlings and brush to speed growth of the planted seedlings
Ground preparation - Cultivation of the soil to create suitable planting positions. This operation may include some element of land drainage in wet areas if soil saturation affects seedling survival / growth potential.
Replanting - Dropping seeds or manual planting of seedlings
Road deconstruction - Subsequent erosion and landsliding from old roads can be reduced by installing waterbars, pulling fill from stream crossings, and putting excavated materials back to reform the original topography.
Logging is by some measures a dangerous occupation. 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. The risks experienced in logging operations can be somewhat reduced, where conditions permit, by the use of mechanical tree harvesters and forwarders.
Logging and safety
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 felling or dragging trees and operation of machinery in the forest.
Logging and the environment
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 may alter stream 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.
Impact of Tree Harvesting
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.
Impact of logging operations
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. Ecologically important lands are sometimes set aside as reserves. Technological advances in logging equipment are reducing ruts and soil disturbance. Processors and Forwarders with Caterpillar tracks or other designs to lower ground pressure help to reduce machine impact . + * Harvesting Systems
Posted by bushganizer258 at 9:30 AM