What Are the Major Sources of Pollutants from Forestry Operations?

Silvicultural nonpoint source pollution impacts depend on site characteristics, climatic conditions, and the forest practice employed. Sediment, nutrients, pesticides, and temperature are pollutants commonly associated with forestry activities.

Pre-Harvest Planning

The objective of this management measure is to ensure that silvicultural activities, including timber harvesting, site preparation, and associated road construction, are conducted in a way that takes into account potential nonpoint source pollutant delivery to surface waters. Preharvest planning has been demonstrated to play an important role in the control of nonpoint source pollution and efficient forest management operations. Components of this measure address key aspects of forestry operations relevant to water quality protection, including the timing, location, and design of harvesting and road construction, the identification of sensitive areas or high-erosion-hazard areas; and the potential for additional cumulative contributions to existing water quality impairments.

Streamside Management Areas (SMA)

This management measure establishes areas along surface waters that are managed to protect the water quality of the adjacent waterbody. Streamside Management Areas (SMAs) protect against soil disturbance and reduce the delivery to waterbodies of sediment and nutrients from upslope activities. Canopy species in SMAs shade waterbodies, which moderates water temperature, and provide the detritus that often serves as an energy source for stream ecosystems. Trees in the SMA also provide a source of large, woody debris to waterbodies.

Road Construction / Reconstruction

Road construction is often the largest source of silviculture-produced sediment. The purpose of this management measure is to reduce the generation and delivery of sediment from road construction or reconstruction. This is to be accmplished by following the preharvest plan layouts and designs for the road system, incorporating adequate drainage structures, and properly installing stream crossings. Other components of this measure include avoiding constructing roads in SMAs, removing debris from streams, and stabilizing areas of disturbed soil such as road fills.

Road Management

The objective of this management measure is to manage existing roads to prevent sedimentation and pollution from runoff-transported materials. This management measure describes how to manage existing roads to minimize erosion, maintain stability, and reduce the risk of failure or decreased effectiveness of drainage structures and stream crossings. Components of this measure include the use of inspections and maintenance actions to prevent erosion of road surfaces and ensure the continued effectiveness of stream crossing structures. The measure also addresses appropriate actions for closing roads that are no longer in use.

Timber Harvesting

This management measure is intended to reduce NPS pollution resulting from timber harvesting operations. The measure includes components for the location of landings, for the operation of groundskidding and cable yarding equipment, and for the prevention of pollution from petroleum products. Harvesting practices that protect water quality and soil productivity can also reduce total mileage of roads and skid trails, lower equipment maintenance costs, and provide better road protection and reduce road maintenance. Appropriate skid trail location and drainage and proper harvesting in SMAs are addressed by this measure. Erosion from the siting and operation of timber harvest operations can be reduced by conducting preharvest planning.

Site Preparation and Forest Regeneration

In some areas mechanical site preparation is of great concern for potential impacts to water quality. This is especially true in areas that have steep slopes on highly erodible soils, or where the site is located in close proximity to a waterbody. Careful regeneration of harvested forest lands is important in providing water quality protection from disturbed soils. This management measure is intended to reduce the impacts of mechanical site preparation and regeneration operations and to confine on-site potential nonpoint source pollution. Components of this measure address keeping slash materials out of drainages, operating machinery on the contour and protecting the ground cover in ephemeral drainages and SMAs.

Fire Management

Prescribed burning is aimed at reducing slash and competition for nutrients among seedlings and protecting against wildfire. Prescribed fires that burn intensely on steep slopes in close proximity to streams and that remove most of the forest floor and litter down to the mineral soil, are most likely to adversely affect water quality. The purpose of this management measure is to reduce the potential nonpoint source pollution and erosion resulting from prescribed fire for site preparation and from methods for suppression of wildfire. Prescribed fires should be conducted under conditions to avoid the loss of litter and incorporated soil organic matter. Bladed firelines should be stabilized to prevent erosion, or practices such as handlines, firebreaks, or hose lays should be used where possible.

Revegetation of Disturbed Areas

Revegetation of areas of disturbed soil can successfully prevent sediment and pollutants associated with the sediment (such as nutrients) from entering nearby streams. The objective of this management measure is to reduce erosion and sedimentation by the rapid revegetation of areas of soil disturbance from harvesting and road construction. The disturbed areas to be revegetated are those localized areas within harvest units or road systems where mineral soil is exposed or agitated such as road cuts, fill slopes, landing surfaces, cable corridors, or skid trails.

Forest Chemical Management

Chemicals used in forest management are generally pesticides (insecticides, herbicides, and fungicides) and fertilizers. Since pesticides may be toxic, they must be properly mixed, transported, loaded, and applied and their containers must be properly disposed of to prevent potential nonpoint source pollution. Fertilizers must also be properly handled and applied since they also may be toxic or may shift surface water energy dynamics, depending on the exposure and concentration. The objective of this management measure is to ensure that the application of pesticides and fertilizers does not lead to contamination of surface waters. Components of this measure include applications by skilled workers according to label instructions, careful prescription of the type and amount of chemical to be applied, and the use of buffer areas for surface waters to prevent direct application or deposition.

Wetland Forest Management

Forested wetlands provide many beneficial water quality functions and provide habitat for aquatic life. The purpose of this management measure is to protect the aquatic functions of forested wetlands

Water Quality Management in Alabama

The Alabama Environmental Management Act authorizes the Alabama Department of Environmental Management (ADEM) to establish and enforce water quality standards, regulations and penalties in order to carry out the provisions of state and federal water quality laws. From that authorization, ADEM Administrative Code prohibits the deposition of pollutants into or the degradation of the physical, chemical, or biological integrity of waters of the state. (see the BMP Manual glossary for definitions). With regard to silviculture, nonpoint source pollutants include, but are not limited to, sediment, organic materials, temperature, trash, pesticides and nutrients (see glossary for definitions and impacts) that are man induced.

In addition, the Alabama Water Pollution Control Act states that ADEM shall have the authority to propose remedial measures necessary to clean up waters that have been determined to be polluted. ADEM advocates, however, that avoiding environmental problems through voluntary application of preventative techniques is much less expensive, more cost effective and practical than restoration after the fact.

The Alabama Forestry Commission’s Role in Best Management Practices

The Alabama Forestry Commission was established and is mandated by Code of Alabama, 1975, Section 9-3-4 (1), to protect, conserve, and increase the timber and forest resources of the state. All citizens of Alabama are our valued customers. However, as the lead agency for forestry in the state, we seek to strike a balance between serving Alabama forest owners’ needs and enhancing the benefits flowing to society from their forests. Our mission is to promote environmentally and economically sound forestry practices, and we are committed to optimizing available resources to achieve this mission.

The Alabama Forestry Commission is not an environmental regulatory or enforcement agency, but it does accept the responsibility to maintain and update Alabama’s Best Management Practices (BMPs) for Forestry whenever necessary to help Alabama’s forestry community meet state water quality needs. The Commission will work in a cooperative manner with all state and federal agencies concerned, and is determined to utilize technical expertise from within and without the forestry community in any BMP revision process.

The Alabama Forestry Commission also accepts responsibility to provide education and technical assistance to landowners, loggers, foresters, vendors and the general public to ensure that good stewardship principles are understood and used.

Purpose of Best Management Practices

Alabama’s Best Management Practices for Forestry are non-regulatory guidelines (except for the U.S. Army Corps of Engineer’s baseline BMPs on pages 16 and 17 which are mandatory) suggested to help Alabama’s forestry community maintain and protect the physical, chemical and biological integrity of waters of the state as required by the Federal Water Pollution Control Act, the Alabama Water Pollution Control Act, the Clean Water Act, the Water Quality Act, and the Coastal Zone Management Act.

The BMPs booklet lays out a framework of sound stewardship practices that, when consistently applied, will contribute positively to maintaining a high degree of water quality flowing from a forest. These BMPs are not intended to be all inclusive. Rational and objective on-site judgment must be applied to ensure that water quality standards are maintained.

The most important guidance that these BMPs can offer the forestry community is to think and plan before you act. Adequate forethought will pay off in two ways: to avoid unnecessary site disturbance or damage in the first place and to minimize the expense of stabilizing or restoring unavoidable disturbances when the operation is finished.

Following sound stewardship principles in carrying out forestry practices will ensure that our forests continue to meet the needs of their owners, provide jobs, forest products, clean water and a healthy environment without costly regulations. Only through sound stewardship principles will all of these needs be met.


Responsibility for maintaining water quality standards during a forestry operation has been broadly interpreted to include all parties involved in the authorization, planning or implementation of the operation. The responsible parties may include professional forestry practitioner(s) such as forest resource managers, timber purchasers, loggers, vendors, forest engineers or others. Due to this inherent responsibility it is in the best interest of all those involved in silvicultural operations to make every effort to prevent and correct violations of state and federal water quality laws, regulations and standards by consistently implementing BMPs.

Additional Resources

A Guide for Forest Access Road Construction and Maintenance in the Southern Appalachian Mountains

The title of this Guide is a little misleading. Although it was originally developed for road construction is Southern Appalachian Mountains the general principals and guidelines set forth in the manual can be and should be applied to all forest road construction. Roads in steeper terrain are more difficult to construct while the degree of difficulty on flatter terrain roads is less, they have a lot in common. This book is a good guide that addresses subjects to be considered in all road construction:

Pre-Construction Planning | Design Guidelines | Surface Drainage | Stream Crossings | Laying out of the Road Getting Ready for Construction | Constructing the Road | Establishing Groundcover | Maintaining Your Road

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