Clearcutting

Clearcutting in Southern Finland

Clearcutting, or clearfelling, is a controversial forestry/logging practice in which most or all trees in a harvest area are cut down. Logging companies and forest-worker unions in some countries still support the practice for safety and economical reasons. Detractors see clearcutting as synonymous with deforestation, destroying natural habitats and contributing to global warming.

Types

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).

• Clearcutting contrasts with selective cutting such as high grading, in which only commercially valuable trees are harvested, leaving the others. This practice this 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'.

• 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.
• Another controversial practice is the wholescale removal of irreplaceable ancient temperate and boreal forest.

Positive perspectives

Limited clearcutting can be practiced to encourage 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.

Clear-cutting is sometimes used by foresters as a method of mimicking disturbance and increasing primary successional species like poplar (aspen), willow and black cherry (North America). Clear-cutting 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.

Negative impacts

Clearcutting can have major negative impacts. These have been cited as soil erosion, poor quality re-growth, increased risk of pest epidemics, increased wildfires, loss of biodiversity, and loss of economic sustainability and increased environmental instability, loss of carbon contributing to global warming and so on. Unfortunately the response of governments around the world has sometimes been to marginalize community, environmental, social and academic concerns and defer to the logging industry.

Old-growth wood often bears the scars of countless centuries, focusing interest on optimally reproductive mid-growth trees, the forest powerhouses that in most market species are 200 to 500 yearts old. In undisturbed environments, old-growth forest shelters many optimal specimens. A number of attempts have been made to ameliorate the effects of clearcutting: encouraging natural regrowth, careful selective seeding (monocropping) and burn-out. However these attempts have to date been poorly managed and sporadic, and not based on unbiased forestry science. Where resource economies do not include purposeful seeding, the resulting clearcut re-growth is always unhealthy and prone to fire damage.

Clearcut re-seeding (that is improperly planned) has all of the same negative fire and disease effects of natural regrowth clearcuts. Another reseeding disadvantage, that is extensive where managed forestry companies exceed cuts and fill in slope margins with compulsory plantings, is mono-crop disease leading to soil failure. For instance, clearcutting on steep slopes always results high soil erosion rates. Tree species that can handle higher soil acidity (associated with soil erosion) and with roots suitable to retain and partially rebuild soil, such as pine trees in monocrop plantations. Unfortunately, extensive use of pine has wiped out millions of hectares of diseased and burned re-growth forests. The pine beetle larvae lacking the checks found in old growth and are now epidemic in North America. Pine beetles burrow into re-growth pine mono-cropping and kill the trees just when they enter their productive life-cycle point of rapid growth that should last 100 to 200 years. Dead clearcut trees accelerate wildfires that are removing increasing amounts of the commercially useful vegetation in their path each year.

Burnouts are not helpful, though they represent the only known option to immediately protect property in the line of active fire. It was once thought that careful clearcut burnouts set to target just certain very congested patches and only certain undergrowth flammables would limit fire damage in expanding clearcut zones. However, this did not limit wild fire incidence or extent across decades. In fact, it did create a huge cache of wild fire fuel, as forest cleaned by burnout become even more stressed by lack of biodiversity, soil erosion and disease. Burnouts are coupled with wildfire suppression. This has disastrously increased re-growth fire fuel: by putting out wild fires, what burned small four decades ago becomes accelerant for much greater fuel mass during inevitable future fires.

See also

Main article: Outline of forestry

• 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

References

• Roy, Vincent, Ruelb, Jean-Claude and Plamondon, André P. (1999). 'Establishment, growth and survival of natural regeneration after clearcutting and drainage on forested wetlands' in Forest Ecology and Management, Volume 129, Issues 1-3, 17 April 2000, Pages 253-267 [1]

External links

• Belt, Kevin and Campbell, Robert, The Clearcutting Controversy - Myths and Facts, West Virginia University, accessed 14 December 2009
• Canadian Broadcasting Corporation (CBC) Digital Archives - Clearcutting and Logging: The War of the Woods
• Clearcutting on the Ritchiewiki
• 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