Clearcutting, or clearfelling, is a controversial forestry/logging practice in which most or all trees in an area are uniformly cut down. Clearcutting, along with shelterwood and seed tree harvests, is used by foresters to create certain types of forest ecosystems and to promote select species that require an abundance of sunlight or grow in large, even-age stands. Logging companies and forest-worker unions in some countries support the practice for scientific, safety, and economic reasons. Detractors see clearcutting as synonymous with deforestation, destroying natural habitats and contributing to climate change.
Many variations of clearcutting exist; the most common professional practices are:
- Standard (uniform) clearcut – removal of every stem (whether commercially viable or not), so no canopy remains.
- Patch clearcut – removal of all the stems in a limited, predetermined area (patch).
- Strip clearcut – removal of all the stems in a row (strip), usually placed perpendicular to the prevailing winds in order to minimize the possibility of windthrow.
- Clearcutting-with-reserves – removal of the majority of standing stems save a few reserved for other purposes (for example as snags for wildlife habitat), (often confused with the seed tree method).
- Slash-and-burn – the permanent conversion of tropical and subtropicals forests for agricultural purposes. This is most prevalent in tropical and subtropical forests in overpopulated regions in developing and least developed countries. Slash-and-burn entails the removal of all stems in a particular area. This is a form of deforestation, because the land is converted to other uses.
Clearcutting contrasts with selective cutting, such as high grading, in which only commercially valuable trees are harvested, leaving all others. This practice can reduce the genetic viability of the forest over time, resulting in poorer or less vigorous offspring in the stand. Clearcutting also differs from a coppicing system, by allowing revegetation by seedlings. Additionally, destructive forms of forest management are commonly referred to as 'clearcutting'.
Clearcutting can have major negative impacts, both for humans and local flora and fauna. A study from the University of Oregon found that in certain zones, areas that were clear cut had nearly three times the amount of erosion due to slides. When the roads required by the clearcutting were factored in, the increase in slide activity appeared to be about 5 times greater compared to nearby forested areas. Clearcutting can also lead to an increased possibility of rapid runoff, loss of economic sustainability in that no timber products are available for a long time after clearcutting, loss of habitat for some wildlife species, unattractive visual effect, greater possibility of unwanted shrub and grasses becoming established, as well as a decrease in property values; diminished recreation, hunting, and fishing opportunities.
Clearcutting can be practiced to encourage the growth and proliferation of tree species that require high light intensity. Generally, a harvest area wider than double the height of the adjacent trees will no longer be subject to the moderating influence of the woodland on the microclimate. The width of the harvest area can thus determine which species will come to dominate. Those with high tolerance to extremes in temperature, soil moisture, and resistance to browsing may be established, in particular secondary successional pioneer species.
Clearcutting can be used by foresters as a method of mimicking disturbance and increasing primary successional species, such as poplar (aspen), willow and black cherry in North America. Clearcutting has also proved to be effective in creating animal habitat and browsing areas, which otherwise would not exist without natural stand-replacing disturbances such as wildfires, large scale windthrow, or avalanches.
In temperate and boreal climates, clearcutting can have an effect on the depth of snow, which is usually greater in a clearcut area than in the forest, due to a lack of interception and evapotranspiration. This results in less soil frost, which in combination with higher levels of direct sunlight results in snowmelt occurring earlier in the spring.
- Clearcutting in British Columbia
- Even-aged timber management
- List of tree species by shade tolerance – shade intolerant and some intermediate species are primarily regenerated with clearcuts
- Seed production and gene diversity
- ^ a b Dr. J. Bowyer; K. Fernholz, A. Lindburg, Dr. J. Howe, Dr. S. Bratkovich (2009-05-28) (pdf). The Power of Silviculture: Employing Thinning, Partial Cutting Systems and Other Intermediate Treatments to Increase Productivity, Forest Health and Public Support for Forestry. Dovetail Partners Inc.. http://dovetailinc.org/files/DovetailSilvics0509.pdf. Retrieved 2009-06-06.
- ^ U.S. Environmental Protection Agency, Washington, DC (1992). "Clear cut." Terms of Environment: Glossary, Abbreviations and Acronyms. p. 6. Document no. EPA-175-B-92-001. Accessed 2011-10-12.
- ^ Center for Biological Diversity, Tucson, AZ. "Clearcutting and Climate Change." Accessed 2011-10-12.
- ^ Helms, John A. (1998-09-01). The Dictionary of Forestry. Society of American Foresters. ISBN 978-0939970735.
- ^ British Columbia Ministry of Forests, Victoria, BC. "Clearcut System Variations." Introduction to Silvicultural Systems. Based on the published workbook: "Introduction to Silvicultural Systems, second edition (July 1999)." Forest Practices Branch.
- ^ Forest Encyclopedia Network Advantages and disadvantages of clearcutting
- ^ Swanson, F.J.; Dyrness, C.T. (1975). "Impact of clear-cutting and road construction on soil erosion by landslides in the western Cascade Range, Oregon". Geology (Geological Society of America) 3 (7): 393-396. doi:10.1130/0091-7613(1975)3<393:IOCARC>2.0.CO;2.
- ^ Toso Bozic (September 14, 2009). "Woodlot Harvest". Government of Alberta: Agriculture and Rural Development. http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/apa3316. Retrieved 7 March 2011.
- ^ Foothill Conservancy, Pine Grove, CA (2001). "Clearcutting in local forests." Foothill Focus. Spring 2001. Accessed 2011-10-12.
- ^ Belt, Kevin and Campbell, Robert (1999). "The Clearcutting Controversy - Myths and Facts." West Virginia University Extension Service. Accessed 2011-12-12.
- ^ Ottosson Löfvenius, M.; Kluge, M., Lundmark, T.. (2003). "Snow and Soil Frost Depth in Two Types of Shelterwood and a Clear cut Area". Scandinavian Journal of Forest Research (Taylor & Francis) 18: 54–63. doi:10.1080/0891060310002345. ISSN 0282-7581.
- Roy, Vincent; Ruelb, Jean-Claude and Plamondon, André P. (1999). "Establishment, growth and survival of natural regeneration after clearcutting and drainage on forested wetlands." Forest Ecology and Management, Volume 129, Issues 1-3, 17 April 2000, pp. 253-267.
- Canadian Broadcasting Corporation (CBC) Digital Archives - Clearcutting and Logging: The War of the Woods
- Congressional Research Service (CRS) Reports regarding Clearcutting, accessed 14 December 2009
- Forest Policy Research page: California citizens to stop Sierra Pacifics plan to clearcut one million acres of Sierra forest, accessed 14 December 2009
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