Equipment Specs


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Forestry Processes
Clearcutting in an Oregon forest.
Clearcutting, also known as clearfelling, is the felling and removal of all the trees in a stand or cut block regardless of age, species, or size of operation. Clearcutting is also recognized as a method of silviculture  in Canada and countries with temperate and boreal growth forests. In logging operations the practice of clearcutting is often referred to as commercial clearcutting. Slash burning is also recognized as a form of clearcutting used more in tropical or sub tropical forests.


[edit] History

Before forests were harvested for timber, people had a harmonious relationship with both the land and with the forest, cutting down only the trees they needed. As society became more agriculture-based, forests were completely cleared out and converted into fields to plant crops. Eventually a need wood to build settlements and ships led to the wide scale logging of North American forests.

[edit] Commercial Clearcutting

At the height of logging during the 1800s to early 1900s, clearcutting was viewed as an economic practice—everything that was usable in the forest was cut down and sent to the sawmill. The majority of logging involved old-growth timber that was entirely useable. The use of creeks, flumes, skid rows, and roads to log and transport virtually thousands of acres of trees resulted in the mass exploitation and ruin of forestry resources. As the implications of clearcut logging on the future of forestry resources became apparent, philosophical attention was eventually paid to forestry preservation.[1] These events eventually shaped the establishment of clearcutting as a viable silviculture practice and not just a commercially based timber harvesting method.

[edit] Clearcutting as Silviculture

Europe was the first continent to reach this stage. In 1760, Germany formalized the selection method in direct reaction to clearcutting and the need for forest regeneration. The selection method focused on an un-even management regeneration approach by establishing different aged trees within a stand. The U.S., lagging behind Europe, did not adopt the selection method until the late 1800s.[2] From the early 1900s through to the 1940s the forestry industry pushed for the selection method. Clearcutting was no longer as a favorable option. By the late 1960s, problems with the selection method began to surface. This led to a shift back towards even-aged silviculture methods. Forestry operations once again resorted to the clearcutting of trees and artificial regeneration measures that involved slash burning and the use of machinery to prepare cut block sites for planting and seeding. Clearcutting became even more common and quickly spread as a practice to other types of forests. By the 1970s, clearcutting was being used to harvest over half the total volume of wood from American forests.[3]

[edit] Process

A patch of old clear cut is visible from a back mountain hiking trail.
The goal of clearcutting as a silviculture system is to create an even-aged stand that is regenerated naturally or through replanting. The forest that is then replanted is called a monoculture forest because all the trees are of the same age and size.[4] Clearcutting is also the most economically feasible method of silviculture used in forest regeneration practices, particularly for tree species that are shade-intolerant and rely on full, direct sunlight for optimal growth and survival.[5]

The practice of clearcutting has spurned much debate in the forestry sector and with environmentalists. In Canada, where clearcutting has actually accounted for about 90 percent[6] of logging practices, the criticisms have been that it results in a loss of biodiversity, contributes to soil erosion and flooding, is the least aesthetically pleasing of all the silviculture systems, and conflicts with environmental and spiritual values. Others argue that clearcutting is simply a process that mimics natural processes such as forest fires, storms, and insect infestation such as the pine beetle.

Public concern over the commercial use of clearcutting has also resulted in the confusion of the practice with what is commonly referred to in logging operations as high grading. High grading is the commercial cut of only the best, high quality trees within a stand. It is not a form of clearcutting, however, because it is not recognized as a method of silviculture and fails to meet specific long-term forestry objectives.[7] High grading is simply an economic means to an end.

[edit] Pros and Cons

Some of the pros of clearcutting are:

  • It is the simplest silviculture method to implement
  • It is the most cost-effective silviculture method to use for forest regeneration after harvesting
  • It provides an opportunity to plant seedlings of a specific species or stock type
  • It is the best silviculture method for planting shade-intolerant species
  • Seedlings grow faster through artificial regeneration than through natural regeneration

Some of the cons associated with clearcutting are:

  • Clearcutting leads to soil erosion, especially from stands harvested on steep slopes or inclines
  • As a practice, it results in the displacement and loss of wildlife, fish, and bird species
  • It results in a loss of carbon in the atmosphere and contributes to global warming
  • It generally leads to a loss of biodiversity such as the removal of animals, insects, fungi bacteria, and plant species that live in the under story part of a forest
  • Clearcutting poses an increased risk of insect infestation
  • It can lead to poor forest regeneration and often demands follow-up regeneration treatment

Sup Buddy

[edit] Variations of Clearcutting

Seed tree cuts and shelterwood cuts are often viewed as slight variations of clear cutting. In a seed tree cut, a certain amount of good quality trees are left unharvested in a stand to act as a seed source and then are cut down at a later time. Small areas being cut and cleared in a given year, with remaining areas being harvested a few years later, after seeding and re-growth has occurred, is characteristic of a shelterwood cut.

[edit] Modern Practices

Problems presented by clearcutting have little to do with its use as a silviculture method, and more to do with how it is applied. Modern clearcutting practices today also tend to take into consideration a number of issues such as biodiversity and wildlife, the economic value of timber, water quality, soil erosion, and aesthetic and recreational appeal. The new Forest Practices Act Code is designed to foster environmental stewardship in forest regeneration practices and this means that clear cut sites in B.C. must be ecologically appropriate. The FPAC address poor past clearcutting practices by limiting cutblock size, requiring riparian reserve along streams, allowing for irregular edges that duplicate natural patterns, and restricting harvesting on steep slopes or unstable soils.[8] Other recent trends in clearcutting include more dispersed cutblocks, longer green-up periods before adjoining areas can be logged, landscape designing to minimize visual impact left by cutblocks, and retention of wildlife within cutblocks. Partial tree cutting in a clearcut area is known as a retention clear cut and allows for groups of trees to remain standing within a cut block.[9] This retention of trees helps protect wildlife habitats while also providing greater visual appeal.

[edit] Types

A strip clearcut is used to harvest a stand over a period of three to seven years by removing several large strips rather than harvesting the entire stand all at once to make use of natural seeding from leave-strips.[10]

An alternate strip clearcut is a variation of a strip clearcut and achieves the same objectives but the cutting is carried out over two phases. In the first pass, long, narrow clearcuts are made with leave strips in between them. The leave strips are narrower than the first pass of strips because they are cut after regeneration has occured in the first pass strips.The second pass of strips are then planted.[11]

The progressive strip clearcut is essentially the same as the alternate strip clearcut except the same objectives are met with cutting occuring in three phases instead of two.[12]

A patch cut is often viewed as a variation of a clearcut in that it involves the complete removal of trees within a stand less than 2.5 acres (1 ha) in size. Each cut is then managed as a distinct opening with regeneration being carried out artificially or naturally.[13]

[edit] References

  1. The Clearcutting Controversy. West Virginia Extension Service. 2008-10-28.
  2. Is Clearcutting a Responsible Forestry Practice? Science in Christian Perspective. 2008-10-28.
  3. Is Clearcutting a Responsible Forestry Practice. Science in Christian Perspective. 2008-10-28.
  4. Clearcutting. Public. 2008-10-28.
  5. Is Clearcutting a Responsible Forestry Practice. Science in Christian Perspective. 2008-10-28.
  6. Silviculture. Boreal Forest. 2008-10-28.
  7. Silviculture. Boreal Forest. 2008-10-28.
  8. Alternatives to Conventional Clearcutting. 2008-10-28.
  9. Alternatives to Conventional Clearcutting. BC Gov. 2008-10-28.]
  10. Clearcut System Variations. BC Gov. 2008-10-28.
  11. Clearcut System Variations. BC Gov. 2008-10-28.
  13. Patch Cut System. BC Gov. 2008-10-28.