Environmental groups criticize clear-cutting as destructive to water,
soil, wildlife, and
atmosphere, and recommend the use of
sustainable alternatives. Clear-cutting impacts the
water cycle, as 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. 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.
Negative impacts Clearcutting can have 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. 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. 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, specifically, a growth of contempt by those familiar with the area for the wooded, planet aftermaths, as well as a decrease in property values; diminished recreation, hunting, and fishing opportunities. Clearcutting decreases the occurrence of natural disturbances like forest fires and natural uprooting. Over time, this can deplete the local seed bank. 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. 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 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. While deforestation rates have slowed since 2004,
forest loss is expected to continue for the foreseeable future. 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.
Positive perspectives 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 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. 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.
Effects on wildlife 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. 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.
In Maine In
Maine, a form of land management known as Outcome Based Forestry (OBF) 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, and research by the
University of Maine's Sustainability Solutions Initiative has found that 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. These practices have sparked
environmental justice concerns regarding the health and well-being of foresters and locals. ==See also==