1 clearly or sharply defined to the mind; "clear-cut evidence of tampering"; "Claudius was the first to invade Britain with distinct...intentions of conquest"; "trenchant distinctions between right and wrong" [syn: distinct, trenchant]
2 having had all the trees removed at one time; "clear-cut hillsides subject to erosion"
3 clear and distinct to the senses; easily perceptible; "as clear as a whistle"; "clear footprints in the snow"; "the letter brought back a clear image of his grandfather"; "a spire clean-cut against the sky"; "a clear-cut pattern" [syn: clear, clean-cut]
Clearcutting or clearfelling is a forestry/logging practice in which the clear majority of all trees in a forest sector are cut down.
There is no agreement upon the minimum area that constitutes a clearcut, but typically, areas smaller than five acres may be labeled patch clearcuts. Clearcutting for conversion to other uses is termed "land conversion" by foresters.
Clearcutting includes both:
Before the advent of modern forestry, clearcutting was practiced as the chief method of logging, with no regeneration for the areas cut, which were converted to other uses or left to regenerate naturally. In areas of the world where replanting is not undertaken, this continues to be the case. In the past and present, this kind of clearcutting without any replanting is practiced in forests where virtually every tree is valuable, as in an old growth forest.
In forestry, clearcutting is practiced to regenerate species that require large disturbed high light intensity environments. In a silvicultural planned clearcut virtually all trees are removed, even trees that are not commercially valuable, in order to achieve the outcome environment desired by commercial foresters, including light and soil factors. Clearcuts that are improperly planned have some of the same negative effects of clearcuts with no plan for regeneration. Clearcutting on steep slopes can result in very high erosion rates, for instance.
In Developing countries and Least developed countries the practice of slash-and-burn is a common form of clearcutting, and in modern times is especially prevalent in tropical and subtropical forests, as a way for overpopulated regions strive to eke out a subsistence.
WildlifeIn many parts of the world monocultures are common and clearcutting is a widespread practice for such plantation timber stands. Conversion from a diverse stand to a monoculture reduces tree diversity by definition, but it also reduces total biotic diversity because many animals and understory vegetation have complex needs fulfilled by only by a forest of diverse composition.
Immediately following a clearcut, there may be a superficial surge of shrub growth along with seedling growth in that high light, elevated resource availability setting. This condition provides ephemeral forage and some habitat for wildlife. The timing of a silvicultural clearcut is sometimes planned with this in mind, sometimes to provide forage for a desirable species and sometimes to prevent an undesirable or overpopulated species from having that forage available.
As a silvicultural practice, the removal of stems or nearly all stems provides an ideal situation for the regeneration of pioneer species, that prefer or require high light, high resource availability and disturbed sites. A clearcut is also the means of regenerating a coppice forest.
Clearcutting is one of many silvicultural treatments that alter the environment for regeneration to optimize harvest. The type of regeneration method used, (clearcutting, selection cutting, etcetera) depends on the land type and the species desired.
Managing for a large area of even aged trees has benefits over multi aged management. Damage to residuals, or trees not cut is minimal in a professional logging operation, but in the developing world, residual trees can be damaged (often fatally) in the removal of the other trees. In a situation where a vast majority of trees are valuable to harvest, it is easier for loggers and economically sound to remove trees in an open clearcut, as opposed to moving equipment around standing trees.
Clearcutting commonly leaves residuals, either trees of value are left standing to stabilize the area or trees of no value or less value are left standing because it was not economically worthwhile to harvest them. The latter practice leads to a kind of high grading. The stunted trees and the undesirable species will grow and re-seed the area, especially where no seed bank or root stock of desirables are present. The less desirable stunted individuals from a valuable tree species will generate less viable individuals, often passing on their less vigorous genes. In the field of forestry planting is often prohibitively expensive and a clearcut often leaves seedlings vulnerable to herbivory. Foresters can combat these costs by planning for natural regeneration through use of species that root sprout, like aspen, or burning of residuals where a fire-dependent seedbank is present, as in jack pine stands.
Clearcutting is commonly criticized since bare soils may be broadly exposed, often leading to unacceptably high erosion rates and loss of biodiversity. Adverse aesthetic impacts typically ensue, broadening the public concern in many natural areas. These impacts diminish the enjoyment of scenic areas for motorists and hikers alike.
Spin from some logging corporations is:
- ''"Clearcutting is a cheaper way to harvest trees that the public associates it with destructive practices and a lack of long term management...and images taken directly after a clearcut are sometimes used politically to imply that the area is mismanaged".
Clearcutting has not only a strongly negative visual impact, but often a strongly negative environmental impact. The impact of periodic clearcutting on a viewshed can reduce their value for housing or nearby recreation. This has led to the creation of the "beauty strip", which is a narrow band of trees left as a buffer to conceal clearcut areas from public view. An unspecified number of silviculturalists are recommending variable retention as an alternative to clearcutting.
Natural disturbancesClearcutting facilitates regeneration of early succession stage species, which are reliant on disturbance for regeneration. Many trees species (e.g. aspen, pines, birch) are shade-intolerant. In nature these trees typically establish themselves only after some disturbance, like a blow down, fire or disease outbreak. Aspen, for example, will actually sucker (re-sprout from the roots) after a harvest. Clear cutting provides conditions optimal for species like aspen, many of which are very important to the timber market.
ManagementHigh-grading and poorly planned partial cuts have done more damage to the forest, in some areas, than clearcutting. Abuses of clearcutting are often easily seen while a poorly managed selection cut may be poorly recognized by the public. Selection cut for the same volume of wood requires more total area of the forest must be harvested, with more roads and skid trail with more potential for soil compaction, erosion and residual stand damage.
What is sometimes called commercial clearcutting is used to maximize income regardless of silvicultural issues. Only trees worth money are removed and whatever regeneration remains may be left in damaged condition. In the case of a poorly planned larger (over 1 km²) clearcut, there are few or no residual patches or wildlife snags left behind and the ground will be highly disturbed and compacted; erosion and poor forest regeneration will result. Some forest types are especially intolerant of clearcutting exposing soils to direct sun and winter rains, which damages soil nutrients and fungi required for healthy forests. Because silvicultural issues involved are complex with many factors to be considered, regulation of the over-use of clearcutting is very difficult. Clearcuts are also used to clear land prior to real estate development projects. Large poorly planned clearcuts are far more destructive than cuts that take into consideration natural topography, and bioregions.
Mitigating measuresDepending on when, where, and the scale of the clearcut takes place effect on the environment can be massive, especially in erosion-prone country if countermeasures are not taken. Commonly clearcuts leave blocks of "reserve" trees that won't be cut. These can be left to minimize the aesthetic impact of a clearcut, to maintain cavity or den trees for wildlife, to maintain biodiversity, or other similar reasons. Conscientious logging will leave standing snags and a mosaic of small "residual patches" for wildlife, and organic matter such as "slash piles" of unusable material are left on-site as ash to fertilize the soil or as partly-burnt wood that will decay into the soil. If logged on frozen ground with low ground pressure machinery, or even horses, the ground can be left generally undisturbed and unbroken which can sometimes let ground cover regenerate quickly. Ground damage can be reduced, on conifer clearcuts, if harvesting machines utilize unmerchantable tree tops and branches to construct routes upon which they travel .
clearcut in German: Kahlschlag
clearcut in French: Coupe rase
clearcut in Dutch: Kaalslag
clearcut in Swedish: Slutavverkning
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