To Cut or Not to Cut: Clear-Cutting and its Impact on the Ecosystem and Biodiversity

By: Laura Hendrick (email)

A clear cut is an area where the trees have been harvested or removed, like a crop. Clear cutting is not only a method of harvesting, but also a method of regeneration. When the trees are removed, we are left with an area that may look devastated, but if often teeming with regrowth and wildlife. Clear cutting is the most cost-effective and biologically acceptable means of regenerating some of our most valuable tree species.

Clear Cut with brush on ground which prevents soil erosion
Figure 1. Clear Cut with brush on ground which prevents soil erosion

 

Why do we clear cut? There are many economical, ecological and social benefits. Economically speaking, trees are used for building construction, paper, books and furniture. Therefore they have a monetary value.

Sometimes we have insects that cause lots of damage to our trees. According to the Forest Service, there was an estimated $901.8 million dollars in damage from 1960 to 1990 from the southern pine beetle . These insects bore into pine trees and introduce a fungus that will later kill the tree. When infestations are found, we will cut the infected area to try and eradicate the beetle. This is called a sanitation cut, but sometimes we do clear cut these areas.

After a clearcut, we are responsible for managing the stand for the future. We can plant pines or allow hardwoods to regenerate naturally and we can also reseed logging roads and trails with species that benefit wildlife and prevent erosion. It is up to us to make sure that we do all we can to lessen the impact.

Logging road planted for wildlife and to prevent erosion
Figure 2. Logging road planted for wildlife and to prevent erosion

To reduce impacts, we use BMP's or Best Management Practices. One important BMP is an SMZ or Stream Management Zone. This is a zone or strip of trees left alongside waterways in clear cuts. SMZ's shade streams and keep them at a constant temperature which is important for aquatic life. They also trap any sediment before it enters the stream. Sediment is a form of pollution. Too much dirt in the water can be detrimental for certain aquatic species. An SMZ, can also act as a corridor for animal movement. Other BMP's are straw bales or silt fences along roadsides, which catch soil before it enters waterways.

An SMZ

Figure 3. An SMZ

Silt Barriers trapping sediment
Figure 4. Silt Barriers trapping sediment

 

When we clear cut an area we create an edge . This is the transition from forest to clear cut or a hard edge. The hard edge that is created along clear cuts can be very diverse. This area can provide many sources of food, escape cover for wildlife and an area for wildlife to rest. Many of bird species and predators prefer edge habitat. Turkeys have been found nesting in these areas. As clear cuts grow in age you may find quail also.

Example of Hard Edge
Figure 5. Example of Hard Edge

 

Clearcuts are very diverse in plants and wildlife. Some tree species that could not compete for light before now have a chance to grow in the open area of a clearcut. Therefore, we may see a change in the stand's species composition. Plant-wise, we not only have trees, but we also have vines, grasses and other herbaceous species competing for a place in the ecosystem. Clearcutting opens up a whole new level of vegetation that otherwise would not be present.

Clear cuts are known for becoming densely vegetated and for having piles of brush scattered, left after the harvest. Some animals seek refuge here. For example, ground nesting birds such as whippoorwills, songbirds, rabbits, foxes and other mammals find clearcuts as their home. Deer love to bed down in clearcuts.

Deer in clear cut
Figure 6. Deer in clear cut

In summary, clearcuts have many benefits: valuable timber products, healthy vigorous regeneration, and wildlife habitat. We can lessen our impact in the clear cut by using BMP's and it is up to us to manage the stand properly for the future.

 

Questions:

  1. Define Regeneration.
  2. How does the Southern Pine Beetle affect trees?
  3. Define BMP and give an example of one.
  4. What is the difference between hard edge and soft edge?
  5. Name 3 wildlife species likely to be found in a clear cut.

Answers:

  1. Regrowth; new growth in a clear cut would vary from small trees from stumps to vines, briars and grasses.
  2. It bores into pines, introducing a fungus that kills the tree.
  3. Best management practice – used to lessen impact on environment. Examples: SMZ's, silt barriers/fences, straw bales
  4. A hard edge has little to no transitional area whereas soft edge (succession) and has a gradual transition from one area to another.
  5. Deer, turkey, quail, rabbits, foxes, whippoorwills

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