Clear Cutting

A clearcut is an area of forestland where most of the standing trees are logged in a single operation, and few trees remain after harvest. Forested buffers are left around streams and lakes, and the area is then replanted within two years of harvest.

There are some similarities between a clearcut harvest and a forest opening caused by natural disturbances such as wildfires, windstorms, flooding and volcanic eruptions. Just like these natural occurrences, clearcuts create open space that many plants and animals need to flourish. Since a clearcut receives more sunlight, growing conditions for sun-loving shrubs, herbs and grasses thrive and provide forage for animals such as deer and elk.

Clearcutting Pros:

  • Full sun conditions. Wide-open spaces allow the most sun for species that require full-sun conditions to thrive.
  • Economy of harvest. Clearcutting represents the most efficient and economical method of harvesting a
    large group of trees.
  • Fewer disturbances to the forest floor. By entering a forest stand once, instead of multiple times over a series of harvest events, the landowner minimizes disturbance to forest soil.

Clearcutting Cons:

  • They look bad. Until the newly planted trees “green up” a hillside, a clearcut is not considered appealing.
  • Habitat disturbance. Clearcutting alters the habitat where trees once stood, and forest inhabitants
    are displaced into new areas.
  • Increased stream flow. Clearcuts allow more water to enter a stream system because water is not being taken up and released by trees in a process called “evapotranspiration.”

Strip Cutting

Strip cutting is used to harvest a stand over a period of three to seven years by removing several strips rather than harvesting the entire stand at once. Strip cutting was developed to take advantage of natural seeding from the leave-strips.

A major concern associated with strip clearcuts is wind damage because the leave-strips expose much more edge for a short period than does one large clearcut. To avoid excessive windthrow, leave-strips should be at least 40 m wide, open only at one end, and harvested as soon as adjacent cleared strips are regenerated, thus minimizing exposure time. Also, boundaries of strips should be carefully located in healthy stands on deep, well-drained soils. Strip clearcuts can be designed in an alternate or progressive fashion.

Shelterwood

In a shelterwood cut, mature trees are removed in two or three harvests over a period of 10 to 15 years. This method allows regeneration of medium to low shade-tolerant species because a“shelter” is left to protect them. Many hardwoods, such as oak, hickory and cherry, can produce and maintain seedlings or sprouts in light shade under a partially cut stand. However, the young trees will not grow and develop fully until the remaining overstory trees are removed.

One benefit to shelterwood harvests is that they provide cover and early successional food sources for wildlife. However, this method of harvest is not recommended for trees with shallow root systems because the remaining trees are more susceptible to wind damage after neighboring trees are removed. Another disadvantage to shelterwood cuts is that they require more roads to be built through the forest, and increase the risk of soil disturbance and damage to the remaining trees during harvesting.

The shelterwood method involves the removal of most of the mature stand at the end of the rotation, but a portion of the mature stand is left standing. The shelterwood method serves three basic purposes:Topreparethe stand for production of abundant seed, Tomodifythe environment in a way that promotes germination and survival of the selected species, Tobuildup the amount and size of advance regeneration to ensure the prompt restocking of the new stand following overstory removal.

Seed Tree Harvesting

In a seed tree harvest, five or more scattered trees per acre are left in the harvested area to provide seeds for a new forest stand. These trees are selected based on their growth rate, form, seeding ability, wind resistance and future marketability.

Wildlife benefit from seed tree harvests in much the same way as they do from a clearcut harvest, except that they also reap the benefits of the seed trees themselves. If left on site indefinitely, seed trees eventually may become snags or downed logs, which are important habitat components for woodpeckers and many other species. Seed trees are also excellent food sources and nesting sites for hawks and other birds.

One disadvantage to seed tree harvests is that the remaining trees are at increased risk of damage from wind, lightening, insect attack and logging of nearby trees. This type harvest may also require the landowner to make future investments in thinning and competition control because of uncontrolled reseeding.

Slash and Burn

Slash and burn agriculture is the process of cutting down the vegetation in a particular plot of land, setting fire to the remaining foliage, and using the ashes to provide nutrients to the soil for use of planting food crops. The cleared area following slash and burn, also known as swidden, is used for a relatively short period of time, and then left alone for a longer period of time so that vegetation can grow again.

Many critics claim that slash and burn agriculture contributes to a number of reoccurring problems specific to the environment. They include:

Deforestation: When practiced by large populations, or when fields are not given sufficient time for vegetation to grow back, there is a temporary or permanent loss of forest cover.

Erosion: When fields are slashed, burned, and cultivated next to each other in rapid succession, roots and temporary water storages are lost and unable to prevent nutrients from leaving the area permanently.

Nutrient Loss: For the same reasons, fields may gradually lose the fertility they once had. The result may be desertification, a situation in which land is infertile and unable to support growth of any kind.

Biodiversity Loss: When plots of land area cleared, the various plants and animals that lived there are swept away. If a particular area is the only one that holds a particular species, slashing and burning could result in extinction for that species. Because slash and burn agriculture is often practiced in tropical regions where biodiversity is extremely high, endangerment and extinction may be magnified.

Selective Cutting

Selective cutting,also known asselective felling, is a more ecologically sustainable practice thanclearcutting. It is designed to maintain an uneven or all-aged forest of trees varying not only in age, but in size and species as well.The staggering of light cuttings in a forest stand as the trees grow and mature also lessens the ecological and visual impactharvestinghas on a forest and provides an opportunity to create gaps in the forest canopy to encouragenatural regeneration. Contrary to clearcutting, the selective harvesting of a timber stand is typically more expensive and produces less timber but is considered ideal for the harvesting and regeneration of shade tolerant species of trees.

In selective cutting, each tree must be individually assessed to determine whether it will be cut, left, measured, counted, or marked. The single most important factor used to determine what trees get harvested is economics. Other factors closely scrutinized include rate of growth, the potential for future growth, health and quality of a tree, spacing, and species type.

Some of the advantages of selective cutting are:

  • It supports more varieties of wildlife than clearcutting
  • It is more resistant to disease and insect manifestations than clearcutting
  • It leaves a lighter ecological footprint
  • It creates a more natural-looking forest stand after harvesting
  • At higher elevations and in northern forests, it encourages growth of desirable shade tolerant tree species