Bighorn National Forest

Timber Resource Management

1. How much of the Bighorn National Forest has been harvested?
2. How much timber is harvested each year on the Bighorn NF?
3. Will all of the Bighorn National Forest be harvested at some point in time?
4. Why is timber harvested?
5. What happens to the forest if trees are not harvested?
6. Does clear cutting on the Bighorn Forest cause deforestation?  
7. How has the timber harvest method changed over time?
8. What other types of harvest methods besides clear cutting are used on the Bighorn National Forest?
9. What adverse effects may be caused by harvesting timber and how are they avoided?
10. How long does it take for trees to grow to a harvestable age?
11. What is old growth and how is it protected on the Forest?
12. What is a roadless area?
13. Does the  Bighorn harvest timber in roadless areas?
14. How do insects and disease affect the health of the forest?
15. Why doesn't the Forest Service allow wildfires to burn naturally?
16. What is a controlled burn or prescribed fire?
17. What is "disturbance ecology" and what is it's role in ecosystem management?
18. What is "biodiversity"?
19. How does the Forest Service determine where it will harvest timber and what the possible effects will be.

1. How much of the Bighorn National Forest has been harvested?

Since 1960, approximately 9% of all forested acres on the Bighorn National Forest have been commercially harvested. An additional 3% has been pre-commercially thinned. Most of the areas harvested 20 to 40 years ago are fully stocked with trees 20 to 30 feet tall. Areas harvested in the last 10 to 20 years consist of trees 10 to 20 feet tall and areas harvested in the last 10 years have young seedlings or saplings ranging in size from a few inches to 5 feet tall.

(Information obtained from the Forest Activities database 2001).

2. How much timber is harvested each year on the Bighorn NF?

Between 1966 and 1992, approximately 14 million board feet MMBF was harvested annually. Approximately 4 MMBF has been annually harvested since 1993.

Each Forest has an Allowable Sale Quantity (ASQ) which is set during the Forest Plan analysis. This figure is a maximum average annual harvest level which may be cut. It is not a goal or a target, but rather a limit to ensure the long term sustainability of the forest.
 

3. Will all of the Bighorn National Forest be harvested at some point in time?

Currently 17% of the Bighorn is designated as Wilderness and will never be harvested. Additional  areas  are managed for other resources such as dispersed backcountry recreation or Research Natural Areas. Still other areas are not considered to be suitable for harvest because of rough terrain or poor accessibility. Approximately 23% of the Bighorn is suitable for timber harvest. However, not even all of these acres will be harvested. The Forest Service utilizes a variety of resource protection measures which protect valuable wildlife habitat, water quality and scenic values and further limit the amount of area treated.

(Information obtained from the Forest GIS database, 2002.)

4. Why is timber harvested?

There are many reasons for harvesting timber, however the decision is always based on individual circumstances. Some of the reasons include:

• Controlling the spread of insects and disease
• Meeting the ever increasing demand for wood products such as paper and lumber
• Maintaining diversity and suitable habitat for a wide variety of wildlife species
• Maintaining jobs and income to local communities.

5. What happens to the forest if trees are not harvested?

The forest is constantly evolving. Trees become established, flourish, die and are replaced by other trees as a result of natural succession. Generally, the first trees to appear are aspen and lodgepole pine. These species thrive for 150 to 200 years and are then gradually replaced by spruce and fir. Spruce and fir stands often thrive on cool north slopes for hundreds of years. Because most forest fires are extinguished before they can affect the successional process, timber harvest is needed to ensure the regeneration of species such as lodgepole pine which require a disturbance such as fire to regenerate.

6. Does clear cutting on the Bighorn Forest cause deforestation?  

No. Deforestation is an often misused term. It only occurs when a forested site is converted from growing trees to growing another crop, as is common in slash and burn agriculture in third world countries. In its most extreme form, deforestation can result in barren ground or desert.

On the Bighorn National Forest, clear cut areas grow back naturally. Within five years of harvest, seedlings are evident throughout the area. By age 15 trees are often over 10 feet tall. By age 30, young, trees between 20 and 30 feet tall occupy the harvested area. In terms of number of trees, approximately 100 trees per acre are cut in a typical clear cut. By the time regeneration is established (5 years) there are 300 to 500 trees per acre on the site.

The forests of the Big Horn mountains were historically subjected to large (thousands of acres), stand-replacing wildfires. Clear cutting mimics some, but not all, of the stand conditions that occur naturally after wildfires.

  7. How has the timber harvest method changed over time?

In the 1960s, clear cuts were generally 100-400 acres in size. During the 1970s, in response to public concern over clear cutting, shelter wood systems (see below) were the dominant harvest type. In an effort to improve elk habitat in the 1980s,most timber harvests on the Bighorn were 5-30-acre clear cuts, thereby created an optional "edge-forage" habitat mix. Recent timber sale planning has considered a mix of harvest systems, including large (several hundred acres) clear cuts that would more closely emulate the historic scale of disturbance events.

8. What other types of harvest methods besides clear cutting are used on the Bighorn National Forest?

The Bighorn utilizes a number of different harvest methods. Selection of harvest methods depends on the objectives of the harvest, stand age, condition and species.

Coppice- Similar to a clearcut, this method produces a new stand from sprouts or root suckers from the harvested trees. It is usually done in aspen forest types.

Seed Tree- An even-aged method in which the new stand develops from seeds that germinate after removal of all the previous stand except a small number of trees left to provide seed. Seed trees are removed after regeneration is established.

Shelterwood- An even-aged method in which a new stand develops beneath the moderated micro-environment provided by varying levels of residual trees. This method is done in incremental steps about every 20 years and may include a preparatory cut to enhance conditions for seed production, an establishment cut to prepare the seed bed and to create a new stand and a removal cut to release established regeneration from competition with the overstory.

Single Tree Selection- This method is generally used to promote uneven-aged stands by removing trees of all size classes until an even distribution of sizes is present.

9. What adverse effects may be caused by harvesting timber and how are they avoided?

Harvesting timber can have adverse effects on the environment. However, with careful planning, these effects can be minimized. For example, many routine mitigation measures, called "Best Management Practices" or BMP's, are incorporated whenever timber is harvested. A few of the many BMP's which the Forest Service uses regularly include:

• Proper road location and construction to reduce sedimentation in streams;
• Maintaining areas of old growth forest for wildlife which prefer mature forest habitat;
• Limiting times of harvest to reduce disturbance to wildlife;
• Harvesting only on suitable lands;
• Ensuring that all harvested stands can be regenerated within five years of harvest.

The Forest Plan also contains Standards and Guidelines (S&G's) which are applied during both the project planning and implementation phases. These S&G's include numerous protection measures which greatly minimize the risk of adverse effects.

As a final protection measure, the Forest Plan and individual projects provide for monitoring the effects of timber sales, as well as other activities. Information from monitoring helps identify problems which can be avoided in future projects.

10. How long does it take for trees to grow to a harvestable age?

Lodgepole pine, which is the primary species for timber harvest on the Bighorn National Forest, generally reaches maturity in 100 to 120 years.
 

11. What is old growth and how is it protected on the Forest?

The primary definition of old growth is old trees for a given site. That is, certain areas of the Bighorn NF primarily grow lodgepole pine, which is considered "old" at 150 years. However, in the Powder River Pass area, trees are known to exceed 500 years in age. Other areas of the Bighorn grow primarily Englemann spruce, which is a longer-lived species, attaining maturity at about 200 years. "Old" forests contain both live and dead trees and have downed logs on the ground. Lodgepole old growth may be the one species on site while Engelmann spruce old growth typically has at least three forest species on site (subalpine fir and lodgepole in addition to the spruce). 

To protect this component of the forest, the Forest Service identifies specific areas with old-growth characteristics in areas which best serve old-growth dependent wildlife species. Other areas which are better suited for timber production because of terrain or access will be harvested. 

12. What is a roadless area?

As a result of the 1964 Wilderness Preservation Act, the Forest Service identified areas for potential designation as Wilderness during two Roadless Area Review and Evaluations (RARE) studies. Areas identified under the RARE studies had to be greater than 5,000 acres and possess primitive characteristics. The best of these areas were designated as Wilderness areas by Congress. Most of the areas which were not determined to be good for wilderness were released for other uses. These areas which were not included in the Wilderness system are still often referred to as "roadless areas" although many contain "two-track" or primitive and historic roads.

13. Does the Bighorn harvest timber in roadless areas?

Not at the present time. The Forest Plan revision is expected to make decisions where timber harvest is appropriate.

14. How do insects and disease affect the health of the forest?

As the forest ages, it becomes more susceptible to attack from insects and disease. On the Bighorn National Forest, the lodgepole pine beetle and dwarf mistletoe present the greatest risk. Endemic levels are always present and are desirable as a food base for wildlife. However, when environmental conditions are right, outbreaks can be widespread and kill thousands of trees. These outbreaks can mar the visual landscape, reduce wildlife habitat, and result in lost revenue from forest products such as timber. On the other hand, insects and disease can create a biologically diverse habitat.
 

15. Why doesn't the Forest Service allow wildfires to burn naturally?

Wildfire affects the forest in many ways. Some effects are good, such as regenerating old stands of lodgepole pine which require fire to open cones, and clearing out dead and down slash which can create catastrophic fire conditions. Other effects are adverse both to man and the environment. For example, loss of personal property can be an unacceptable risk to private property owners with the Forest Boundary. And uncontrolled levels of sediment and ash in streams can destroy valuable fishery habitat.

In most cases, the Forest Service believes that the adverse effects of uncontrolled fire are not offset by the beneficial effects. One exception is wildfire occurring in wilderness areas, which is allowed to burn unless there is a potential risk that the burn will leave the wilderness and threaten other areas.

16. What is a controlled burn or prescribed fire?

These terms are synonymous. The Forest Service routinely uses fire as a management tool, but it is usually used in the form of low intensity controlled burns. These fires are planned and carried out under carefully measured conditions and are always within a contained area. They are generally used to reduce fire hazard or rejuvenate stagnant areas of grass and shrubs which are important winter habitat for deer and elk.

17. What is "disturbance ecology" and what is its role in ecosystem management?

Disturbance ecology deals with changes to ecosystems generally caused by such factors as fire, insects, disease and floods. Awareness and understanding of disturbance ecology and the role disturbance plays in ecosystem dynamics is essential in understanding ecosystem potentials and the consequences of management choices. Ecosystems constantly change in ways that are only partially predictable. To have an effective ecosystem management policy, resource managers and the public must understand the nature of ecological resiliency and stability and the role of natural disturbance on sustainability.

18. What is "biodiversity"?

Biodiversity or biological diversity refers to the variety of life forms and processes within an area. Included in the consideration of diversity are the complexities of genetic variation, number and distribution of species, and the ways in which the variety of biologic communities interact and function. The Bighorn has adopted a three-part approach to the conservation of biological diversity.

• Coarse Filter Analysis- Focuses on the function, composition and structure of ecosystems as a whole. This level addresses most species needs.
• Fine Filter Analysis- Addresses the those species which require special attention due to unique habitat requirements or rarity of species numbers.
• Range of Natural Variability Analysis- Provides a context for assessing current and projected forest conditions.

19. How does the Forest Service determine where it will harvest timber and what the possible effects will be.

Individual harvest proposals are located by a variety of methods. Generally, the Forest Plan outlines areas where timber harvest may occur. More specific projects are identified from this plan and listed on a five-year action plan. Sometimes natural disturbances such as a tornado or large fire may initiate the need for a given project.

For analyzing the effects of proposed projects. The Forest Service follows the procedures detailed in the National Environmental Policy Act (NEPA), and National Forest Management Act (NFMA). These Acts provide a process for determining what activities should occur, where they should occur, and what their potential effects on the environment may be.

USDA Forest Service, Bighorn National Forest
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Last modified May 19, 2004