Clearcutting, clearfelling or clearcut logging is a forestry/logging practice in which most or all trees in an area are uniformly cut down. Along with shelterwood and seed tree harvests, it is used by foresters to create certain types of forest ecosystems and to promote select species [1] that require an abundance of sunlight or grow in large, even-age stands. [2] Logging companies and forest-worker unions in some countries support the practice for scientific, safety and economic reasons, while detractors consider it a form of deforestation that destroys natural habitats [3] and contributes to climate change. [4] Environmentalists, traditional owners, local residents and others have regularly campaigned against clearcutting, including through the use of blockades and nonviolent direct action. [5]
Clearcutting is the most economically efficient method of logging.[ citation needed ] It also may create detrimental side effects, such as the loss of topsoil, the costs of which are intensely debated by economic, environmental and other interests. In addition to the purpose of harvesting wood, clearcutting is used to create land for farming. [6] Ultimately, the effects of clearcutting on the land will depend on how well or poorly the forest is managed, [7] and whether it is converted to non-forest land uses after clearcuts. [8]
While deforestation of both temperate and tropical forests through clearcutting has received considerable media attention in recent years, the other large forests of the world, such as the taiga, also known as boreal forests, are also under threat of rapid development. In Russia, North America and Scandinavia, creating protected areas and granting long-term leases to tend and regenerate trees—thus maximizing future harvests—are among the means used to limit the harmful effects of clearcutting. [9] Long-term studies of clearcut forests, such as studies of the Pasoh Rainforest in Malaysia, are also important in providing insights into the conservation of forest resources worldwide. [10]
Many variations of clearcutting exist; the most common professional practices are: [11]
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.[ citation needed ] 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 be differentiated into
Confusion between these different uses of the term is common. Furthermore, as indicated above many variations mean technically correct usage may not be descriptive enough to know what is meant on that particular occasion.[ citation needed ]
A clearcut is distinguished from selective logging where typically only a few trees per hectare are harvested in proportions dictated by management objectives. Clearcut logging is also distinct from wildland fire use, and from forest thinning. In these latter two it is common practice to leave trees that are considered undesirable, such as those that are too diseased, stunted or small to be marketable. Selective logging is usually practiced in areas with access to infrastructure.[ citation needed ]
Environmental groups criticize clear-cutting as destructive to water, soil, wildlife, and atmosphere, and recommend the use of sustainable alternatives. [14] Clear-cutting impacts the water cycle. Trees hold water and topsoil. Clear-cutting in forests removes the trees which would otherwise have been transpiring large volumes of water and also physically damages the grasses, mosses, lichens, and ferns populating the understory. Removal or damage of the biota reduces the local capacity to retain water, which can exacerbate flooding and lead to increased leaching of nutrients from the soil. The maximum nutrient loss occurs around year two and returns to pre-clearcutting levels by year four after the cut. [15]
Removing trees surrounding stream banks prevents shading of the water body, which raises the temperature of riverbanks and rivers. Because the trees no longer hold down the soil, riverbanks increasingly erode as sediment into the water, creating excess nutrients which exacerbate the changes in the river and create problems miles away, in the sea. [14] Clear cutting on a large scale in a watershed can cause sediment and nutrients that leach into the streams cause the acidity of the stream to increase. [15] The nutrient content of the soil was found to return to five percent of pre-clearcutting levels after 64 years. [16]
Clearcutting can have negative impacts, both for humans and local flora and fauna. [17] 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. The roads built for clearcutting interrupt normal surface drainage because the roads are not as permeable as the normal ground cover. The roads also change subsurface water movement due to the redistribution of soil and rock. [18] Clearcutting may lead to increased stream flow during storms, loss of habitat and species diversity, opportunities for invasive and weedy species, and negative impacts on scenery, [19] specifically, a growth of contempt by those familiar with the area for the wooded, planet aftermaths, [20] as well as a decrease in property values; diminished recreation, hunting, and fishing opportunities. [21] Clearcutting decreases the occurrence of natural disturbances like forest fires and natural uprooting. Over time, this can deplete the local seed bank. [22]
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 and earlier peak runoff. [23]
The world's rain forests could completely vanish in a hundred years at the current rate of deforestation. Between June 2000 and June 2008, more than 150,000 km2 (58,000 sq mi) of rainforest were cleared in the Brazilian Amazon. Huge areas of forest have already been lost. For example, only eight to fourteen percent of the Atlantic Forest in South America now remains. [24] [25] While deforestation rates have slowed since 2004, forest loss is expected to continue for the foreseeable future. [26] Farmers slash and burn large parcels of forest every year to create grazing and croplands, but the forest's nutrient-poor soil often renders the land ill-suited for agriculture, and within a year or two, the farmers move on. [27]
Clearcutting can be practiced to encourage the growth and proliferation of tree species that require high light intensity. [28] 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. [2] 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.[ citation needed ]
Clearcutting can be used by foresters as a method of mimicking a natural 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.
Clearcuts are used to help regenerate species that cannot compete in mature forests. A number of them are aspen, jack pine, and, in areas with poor soils, oaks—are important species for both game and nongame wildlife species. Clearcutting can also lead to increased vascular-plant diversity in the area. This is most pronounced after a couple years of clearcutting and in herb-rich forests where scarification took place. [22]
No significant changes in water temperature were observed when patch clearcutting was done 100 ft (30 m) away from a river. This suggests that patch clearcutting is a possible solution to concerns about changes in water temperature due to clearcutting. The effects of clearcutting on soil nutrient content were not examined in this study. [29]
More recently, forest managers have found that clearcutting oak stands helps regenerate oak forests in areas of poor soil. The tree canopies in oak forests often shade out the ground, making it impossible for newly sprouted oaks to grow. When the mature trees are removed, the saplings stand a chance of recruiting into the forest. [30]
Clearcutting's main destruction is towards habitats, where it makes the habitats more vulnerable in the future to damage by insects, diseases, acid rain, and wind. Removal of all trees from an area destroys the physical habitats of many species in wildlife. Also, clearcutting can contribute to problems for ecosystems that depend on forests, like the streams and rivers that run through them. [31]
In Canada, the black-tailed deer population is at further risk after clearcutting. The deer are a food source for wolves and cougars, as well as First Nations and other hunters. While deer may not be at risk in cities and rural countryside, where they can be seen running through neighbourhoods and feeding on farms, in higher altitude areas they require forest shelter. [32]
In Maine, a form of land management known as Outcome Based Forestry (OBF) [33] allows for a wide range of harvesting as long as the removed trees do not exceed the amount of tree growth. Since implemented, this program has led to large-scale clearcutting and monoculture tree planting, [33] and research by the University of Maine's Sustainability Solutions Initiative has found that 8,000,000 acres (3,200,000 ha) of certified forest land in (primarily northern) Maine is being overharvested, leading to reduced long-term stability of timber harvests and increased erosion and pollution in the watershed.[ citation needed ] These practices have sparked environmental justice concerns regarding the health and well-being of foresters and locals.[ citation needed ]
Logging is the process of cutting, processing, and moving trees to a location for transport. It may include skidding, on-site processing, and loading of trees or logs onto trucks or skeleton cars. In forestry, the term logging is sometimes used narrowly to describe the logistics of moving wood from the stump to somewhere outside the forest, usually a sawmill or a lumber yard. In common usage, however, the term may cover a range of forestry or silviculture activities.
Silviculture is the practice of controlling the growth, composition/structure, as well as quality of forests to meet values and needs, specifically timber production.
An old-growth forest is a forest that has developed over a long period of time without disturbance. Due to this, old-growth forests exhibit unique ecological features. The Food and Agriculture Organization of the United Nations defines primary forests as naturally regenerated forests of native tree species where there are no clearly visible indications of human activity and the ecological processes are not significantly disturbed. One-third of the world's forests are primary forests. Old-growth features include diverse tree-related structures that provide diverse wildlife habitats that increases the biodiversity of the forested ecosystem. Virgin or first-growth forests are old-growth forests that have never been logged. The concept of diverse tree structure includes multi-layered canopies and canopy gaps, greatly varying tree heights and diameters, and diverse tree species and classes and sizes of woody debris.
A secondary forest is a forest or woodland area which has regenerated through largely natural processes after human-caused disturbances, such as timber harvest or agriculture clearing, or equivalently disruptive natural phenomena. It is distinguished from an old-growth forest, which has not recently undergone such disruption, and complex early seral forest, as well as third-growth forests that result from harvest in second growth forests. Secondary forest regrowing after timber harvest differs from forest regrowing after natural disturbances such as fire, insect infestation, or windthrow because the dead trees remain to provide nutrients, structure, and water retention after natural disturbances. Secondary forests are notably different from primary forests in their composition and biodiversity; however, they may still be helpful in providing habitat for native species, preserving watersheds, and restoring connectivity between ecosystems.
Selection cutting, also known as selection system, is the silvicultural practice of harvesting trees in a way that moves a forest stand towards an uneven-aged or all-aged condition, or 'structure'. Using stocking models derived from the study of old growth forests, selection cutting, also known as 'selection system', or 'selection silviculture', manages the establishment, continued growth and final harvest of multiple age classes of trees within a stand. A closely related approach to forest management is Continuous Cover Forestry (CCF), which makes use of selection systems to achieve a permanently irregular stand structure.
Patch cuts are logging cuts too small to be considered clearcuts, and are instead considered a form of selection cut. A typical patch cut might be 2-3 tree lengths. Below a certain size, seedling regeneration advantage shifts from the shade intolerant species favored in clearcuts to the shade tolerant species favored by selection harvests.
Forest management is a branch of forestry concerned with overall administrative, legal, economic, and social aspects, as well as scientific and technical aspects, such as silviculture, forest protection, and forest regulation. This includes management for timber, aesthetics, recreation, urban values, water, wildlife, inland and nearshore fisheries, wood products, plant genetic resources, and other forest resource values. Management objectives can be for conservation, utilisation, or a mixture of the two. Techniques include timber extraction, planting and replanting of different species, building and maintenance of roads and pathways through forests, and preventing fire.
The following outline is provided as an overview of and guide to forestry:
Variable retention is a relatively new silvicultural system that retains forest structural elements for at least one rotation in order to preserve environmental values associated with structurally complex forests.
The extensive and rapid clearing of forests (deforestation) within the borders of Nigeria has significant impacts on both local and global scales.
Canada's boreal forest is a vast region comprising about one third of the circumpolar boreal forest that rings the Northern Hemisphere, mostly north of the 50th parallel. Other countries with boreal forest include Russia, which contains the majority; the United States in its northernmost state of Alaska; and the Scandinavian or Northern European countries. In Europe, the entire boreal forest is referred to as taiga, not just the northern fringe where it thins out near the tree line. The boreal region in Canada covers almost 60% of the country's land area. The Canadian boreal region spans the landscape from the most easterly part of the province of Newfoundland and Labrador to the border between the far northern Yukon and Alaska. The area is dominated by coniferous forests, particularly spruce, interspersed with vast wetlands, mostly bogs and fens. The boreal region of Canada includes eight ecozones. While the biodiversity of regions varies, each ecozone has characteristic native flora and fauna.
Shelterwood cutting removes part of the old forest stand to allow for a natural establishment of seedlings under the cover of the remaining trees. Initial cuttings give just enough light to allow for the regeneration of desired species. Subsequent cuttings give the new seedlings more light and fully pass the growing space to the new generation. Shelterwood systems have many variations and can be adapted to site conditions and the goals of the landowner. There are concerns associated with this silvicultural system due to windthrow and high costs as well as advantages due to improved aesthetics and cost savings from natural regeneration.
Deforestation is one of the most serious environmental issues in Sri Lanka. Sri Lanka's current forest cover as of 2017 was 29.7%. In the 1920s, the island had a 49 percent forest cover but by 2005 this had fallen by approximately 26 percent. or 24-35%. Between 1990 and 2000, Sri Lanka lost an average of 26,800 ha of forests per year. This amounts to an average annual deforestation rate of 1.14%. Between 2000 and 2005 the rate accelerated to 1.43% per annum. However, with a long history of policy and laws towards environmental protection, deforestation rates of primary cover have decreased 35% since the end of the 1990s thanks to a strong history of conservation measures. The problem of deforestation in Sri Lanka is not as significant in the southern mountainous regions as it is in northern and lowland southern Sri Lanka, largely due to the nature of environmental protection.
Even-aged timber management is a group of forest management practices employed to achieve a nearly coeval cohort group of forest trees. The practice of even-aged management is often pursued to minimize costs to loggers. In some cases, the practices of even aged timber management are frequently implicated in biodiversity loss and other ecological damage. Even-aged timber management can also be beneficial to restoring natural native species succession.
Mycoforestry is an ecological forest management system implemented to enhance forest ecosystems and plant communities, by introducing the mycorrhizal and saprotrophic fungi. Mycoforestry is considered a type of permaculture and can be implemented as a beneficial component of an agroforestry system. It can enhance the yields of tree crops and produce edible mushrooms, an economically valuable product. By integrating plant-fungal associations into a forestry management system, native forests can be preserved, wood waste can be recycled back into the ecosystem, carbon sequestration can be increased, planted restoration sites are enhanced, and the sustainability of forest ecosystems are improved. Mycoforestry is an alternative to the practice of clearcutting, which removes dead wood from forests, thereby diminishing nutrient availability and reducing soil depth.
Forest conservation is the practice of planning and maintaining forested areas for the benefit and sustainability of future generations. Forest conservation involves the upkeep of the natural resources within a forest that are beneficial for both humans and the ecosystem. Forests provide wildlife with a suitable habitat for living which allows the ecosystem to be biodiverse and benefit other natural processes. Forests also filter groundwater and prevent runoff keeping water safe for human consumption. There are many types of forests to consider and various techniques to preserve them. Of the types of forests in the United States, they each face specific threats. But, there are various techniques to implement that will protect and preserve them.
Deforestation in British Columbia has resulted in a net loss of 1.06 million hectares of tree cover between the years 2000 and 2020. More traditional losses have been exacerbated by increased threats from climate change driven fires, increased human activity, and invasive species. The introduction of sustainable forestry efforts such as the Zero Net Deforestation Act seeks to reduce the rate of forest cover loss. In British Columbia, forests cover over 55 million hectares, which is 57.9% of British Columbia's 95 million hectares of land. The forests are mainly composed of coniferous trees, such as pines, spruces and firs.
The Japanese temperate rainforest is well sustained and maintains a high biodiversity. One method that has been utilized in maintaining the health of forests in Japan has been afforestation. The Japanese government and private businesses have set up multiple projects to plant native tree species in open areas scattered throughout the country. This practice has resulted in shifts in forest structure and a healthy temperate rainforest that maintains a high biodiversity.
Continuous cover forestry is an approach to the sustainable management of forests whereby forest stands are maintained in a permanently irregular structure, which is created and sustained through the selection and harvesting of individual trees. The term "continuous cover forestry" does not equate exactly to any one particular silvicultural system, but is typified by selection systems. For example, coppice with standards and Reiniger's target diameter harvesting are also continuous cover forestry. Different existing forest stands may require different silvicultural interventions to achieve a continuously productive irregular structure. Crucially, clearcutting and other rotational forest management systems are avoided.
The Maybeso Experimental Forest is an experimental forest on Prince of Wales Island in Alaska. It is near Hollis, Alaska in the Tongass National Forest and is administered by the United States Forest Service. The area of the forest is approximately 1,101 acres (446 ha), with a peak elevation of 2,953 feet (900 m). The forest was established in 1956 to examine the effects of large-scale clearcut timber harvesting on forest regeneration and anadromous salmonid spawning areas. The Maybeso Experimental Forest is the site of the first large-scale clearcut logging operation in Southeast Alaska, and nearly all commercial forest was removed from the area between 1953 and 1960. Presently, the forest is an even-aged, second-growth Sitka spruce and Western hemlock forest.
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