Authors: James T. Walters, former Extension Associate, Department of Forestry, College of Natural Resources, Virginia Tech and James E. Johnson, Associate Dean of Outreach, College of Natural Resources, Virginia Tech.
Publication Number: 420-144, posted March 2000
Chapter 2: Forest Management And Water Quality
Water quality is defined by its physical, chemical, and biological properties. Water quality indicates the suitability of water for a particular purpose, such as human consumption or fish habitat. The quality of water on a site is influenced by climate, geology, topography, vegetation, and disturbances. It is important to understand that natural water quality can be good or poor, and that water quality is not synonymous with water pollution.
Forests generally have much better water quality than similar sites used for agriculture, industrial production, or residential areas. The importance of water quality in forests will increase as more forestland is developed for other land uses. Water quality in forests is most easily affected when we cause changes to the soil or leaf litter, or remove vegetation from the forest. However, sustainable forest management activities have very little long-term impact on water quality - even on the most sensitive sites.
Non-point source pollution (NPSP) usually refers to regional water quality degradation, where the source of the pollution is not easily identified. Important types of non-point source pollution are sediments, organic materials, nutrients, chemicals, and elevated temperature. Each of these types of NPSP influences an important component of water quality and stream habitat.
For example, nitrates in fertilizer may run off from a farmer's field into an adjacent stream. A small amount of this fertilizer may be absorbed into the natural system. However, if many farmers in the county had nitrate losses, the impacts on water quality could be very severe. Nitrate pollution can negatively affect drinking water and fish habitat.
There are several management strategies for preventing NPSP from your forest. These strategies include minimizing erosion of soil from your property, preventing losses of chemicals, avoiding temperature change in your streams, and protecting sensitive wetland areas.
Strategy #1: Minimize Soil Erosion from your Forest
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Erosion occurs when water transports soil from one location to another. Soil erosion is a natural process that has certainly influenced the topography of Virginia. However, when erosion exceeds natural rates it can be a source of water pollution. Steep, bare slopes can cause very rapid runoff of rainwater and melting snow. If water travels across bare soil, the potential for erosion is much greater. The rapid flow of water will carry soil particles downstream until the flow becomes slower, and the soil particles will then be deposited on the bottom of the stream. This process is called sedimentation. Erosion and sedimentation decrease the sustainability of our forests.
Sedimentation can cause problems for many organisms that live in streams. When soil particles are flowing in the water, they can clog the gills of fish and disrupt mussel feeding and reproduction. When the sediment is deposited on the bottom of the stream, it can degrade habitat and smother aquatic life.
The Virginia Department of Forestry has developed a list of forest management activities that are recommended to prevent soil erosion. These activities are called Best Management Practices (BMP's). Most loggers and foresters are interested in implementing BMP's in forests where they work. Landowners can also implement several important BMP's that can protect water quality. These include: maintaining a vegetated Streamside Management Zone; ensuring that forest roads are properly located, designed, and constructed; ensuring that the timber buyer has a good harvesting plan; and enforcing the terms of your timber sale contract.
A streamside management zone (SMZ) is a vegetated strip of land adjacent to a stream, pond, lake or sinkhole. SMZ's are also frequently called riparian zones, riparian buffers, and filter strips. Maintenance of a vegetated SMZ prevents erosion by protecting the stream banks and slowing runoff into the stream. The Virginia Department of Forestry recommends using SMZ's, in conjunction with other Best Management Practices, to meet federal water quality standards.
It is very important to maintain vegetation and leaf litter in your SMZ. Leaf litter is composed of fresh and decomposed leaves on top of the soil. The litter layer and the roots of trees, shrubs, and grasses hold soil and organic matter in place. It is recommended that you do not remove understory vegetation and that you harvest no more than half of the tree crown coverage from your SMZ. Crown coverage is the area on the ground that is covered by the branches of your trees.
Many landowners prohibit the operation of equipment in their streamside management zones. The equipment used in forestry can cause damage to vegetation or the leaf litter in the SMZ and expose bare soil that is easily eroded. If you do harvest trees from the SMZ, consider requiring the logger to winch trees from the area.
The best width for your SMZ depends on several factors, including soil type, slope, and type of vegetation. The Department of Forestry recommends a buffer of at least 50 feet on each side of most streams. Intermittent streams, which flow only during wet periods, only require 25 feet on each side. However, a larger SMZ is appropriate for trout streams, streams that lead to municipal water supplies, and streams adjacent to steep slopes. It is wise to contact your county forester or consulting forester when you establish a streamside management zone. SMZ recommendations should be an integral part of your forest management plan.
Good roads are valuable assets to your forest because they give you access to perform management activities. Your forest roads must be large enough for use by log trucks and equipment if you plan to harvest timber. Road access is valuable and road maintenance costs can be very high, so it is important to carefully plan the road system for your forest.
Poorly designed and constructed roads are a major source of erosion from forests, particularly on the steep slopes found in western Virginia. Uncontrolled water drains from roads quickly, causing rapid runoff of large amounts of water that can cause erosion on your road, in your ditches, in the adjacent forest, and on the stream banks. This erosion results in the sedimentation of streams and rivers.
The best way to prevent erosion from your forest road is to manage water by slowing drainage and diverting runoff. Slowing drainage allows water to soak into the soil. Diverting runoff distributes it from the road across the tract, so the leaf litter slows water velocity. A carefully designed plan that addresses drainage and runoff should be developed before you begin construction of your forest road.
A good road plan will locate the path of the road and describe how the road should be constructed. These details are important information for foresters, timber buyers, and road contractors because they are needed to prepare an estimate on the cost for the road. Basic water management tools that may be included in your road plan are road grade location, water turnouts, dips, ditches, culverts, gravel, vegetation, daylighting, stream crossings, and gates.
The location of road grades (or slope of the road) is important because water drains slower on a more level road. The best roads have gentle grades so that water runoff is slower. Roads on steep slopes are less desirable. Foresters usually measure road grades in "percent" slope. Basically, the higher the slope percentage, the steeper the road. The Virginia Department of Forestry recommends that road grades do not exceed 10%, but steeper slopes of 15% are acceptable for distances less than 200 feet. Strategically positioning roads along slopes can result in small grades on steep terrain like that in western Virginia. The road construction associated with minimizing the grade may increase costs, but it is less expensive than the poor access or high erosion rates commonly associated with poorly designed roads.
Rolling and broad-based dips are designed to remove water from the road by directing it into a drainage ditch or the forest litter layer. Dips are most commonly found on flatter roads, where water would form a channel in the road. Road dips are installed while your road is being graded and require no materials except gravel and rock.
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A water turnout is a small diversion ditch that disperses water from the road's primary drainage ditch.
Properly located turnouts reduce the cost of your road because they can be substituted for more expensive
drainage structures. Water turnouts are easily constructed with regular road construction machinery.
They direct water from the ditch into a brush pile, a small earth dam, or a pile of large rocks so that
the water can drain through natural systems. Water turnouts require regular maintenance because they
cease to work when they fill with sediment. Turnouts are very important near streamside management
zones because they prevent runoff from forming a channel into the stream.
Culverts are designed to remove water from the road ditches. Metal or plastic culverts are commonly used, but a culvert made from logs or well pipe may be adequate for temporary drainage. Manufactured culverts are popular on permanent roads because they last longer and require less maintenance. Regardless of the culvert type, it is very important to use a culvert of sufficient size. In general, larger culverts are required for larger watersheds and for steeper terrain, which drains more quickly. The smallest culvert that may be used is 15 inches, but larger culverts are required in many situations. Your county forester can advise you on the proper culvert size for your forest road.
Gravel is an important material in the construction of forest roads. It prevents erosion by dispersing the impact of raindrops and surface runoff. A stream of water that would cause erosion in bare soil may simply splash off gravel. Furthermore, a road with gravel has improved trafficability during wet weather. Gravel provides a strong foundation for your road so that heavy equipment does not make ruts. In many areas of western Virginia, gravel is relatively inexpensive and should be used liberally. Your forester and road contractor can identify areas where gravel will be most beneficial.
Establishment of vegetation can be very effective for minimizing runoff on rarely traveled roads. Seeding of bare roads is recommended by the VDOF. There are a wide variety of plants that you can place on your roads, but grasses are most commonly planted. Grasses grow quickly, are easily planted, slow runoff tremendously, and have food value for some wildlife species. Furthermore, grasses do not block the road from occasional use. Farm supply stores generally sell varieties of grass that you can plant yourself and that will grow well in your area. They also carry straw and mulches that help grass to grow during dry summer months.
The Virginia Department of Forestry recommends seeding with a combination of main crop, legumes and grains/grasses to equal a total of 100 to 150 pounds of seed per acre. Common main crop grasses are ryegrass and fescue. Suggested legumes include lespedeza, crownvetch, flatpeas, and alfalfa. Grains and grasses that might grow well include red top grass, weeping lovegrass, foxtail millet, and hybrid bermudagrass.
The use of exotic species is discouraged in sustainable forestry. However, exotic grasses are often seeded after a timber harvest because they are easier to establish than native grasses. They serve the immediate task of preventing erosion from bare soil. However, native grasses should also be seeded and encouraged so that they can take the place of exotics. Native species that you may be able to establish include switchgrass, big bluestem, Indiangrass, and gamagrass.
"Daylighting" refers to cutting trees adjacent to the roads that they would shade. The number of trees that should be removed depends mostly on tree size and the season you plan to use the road. Roads that will be used in the winter must also be well daylighted because of the shorter days. In general, a road should receive sufficient direct sunlight every day so that drying can occur quickly.
Poorly designed stream crossings expose the stream banks to erosion and disturb the bottom of the stream. The county forester can help you to make decisions about stream crossings. Your forester is likely to recommend that you cross your stream with either a bridge or a culvert. Larger streams may require federal and state permits before stream crossings can be installed.
Bridges are the best type of permanent stream crossing, but they are also the most expensive to construct. If the forest road is not used on a regular basis, then a permanent bridge is probably not feasible. Temporary bridges are a good alternative if you will only use the stream crossing periodically. Some loggers and timber buyers may own a portable temporary bridge that they use during logging. You can also rent temporary bridges from local soil and water conservation districts and the Virginia Department of Forestry. Regardless of the type of bridge you use, the stream banks must provide a solid foundation for the bridge and the road should cross the stream at a right angle.
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Culvert crossings are desirable for smaller streams because they are less expensive than bridges, but can
still be used as a permanent crossing. The Department of Forestry has developed minimum culvert sizes for
permanent and temporary stream crossings. Culverts should be placed in a location that provides a solid
foundation and should be covered with solid fill material. Improperly installed culverts can create
erosion problems that can be very expensive to repair.
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Rock fords are sometimes an adequate stream crossing, but cause more disturbance than bridges or culverts. The key to a successful ford crossing is to locate it in a wide, shallow site where the stream has a natural rock base and water levels are lower. Fords are ideally used only as a temporary crossing with little traffic. Fords should be placed where the road approaches the stream at a right angle and the banks are low and stable. Rock is generally placed on the approaches to a ford for at least 50 feet on each side of the stream.
A frequently overlooked, but very important, road structure is a gate. When you are finished using a road, you should install a locked gate to control access. Unauthorized use of the road can result in vandalism of water management structures. For example, a pickup truck could form ruts through water bars during wet periods. The water that flows from the road might then form a channel through the water bar, resulting in increased runoff velocity and erosion. Elaborate gates are not necessary to control access; a simple metal gate attached to wood posts will often suffice.
Regardless of the type of water management structures you use on your forest road, it is very important that the road be installed properly. You and the road contractor should reach an agreement on the type of road to be constructed and the standards the road must meet. These standards should be thoroughly outlined in the road building contract and pre-harvest plan. It might be helpful if the county forester is involved with the road design and installation. The forester can provide valuable input based on recent laws governing water quality and road construction. Finally, it is important to maintain your forest road by adding gravel when necessary, cleaning ditches and turnouts, grading the road, and replacing old culverts.
A typical timber sale contract contains several conditions regarding water quality. Some contractual conditions, such as boundaries of the timber around streams, are found in the terms of the sale. Other conditions will place stipulations on the logistics of the timber harvest. In particular, these stipulations apply to the construction of skid trails and log landings and the "close-down" requirements for the harvest. It is a good idea to ensure that the timber buyer has a harvesting plan that considers these stipulations.
Skid trails are small, temporary roads used for dragging logs to the loading area. A logger generally makes several "primary" skid trails that branch out into the timber harvest area. These primary skid trails receive a great deal of skidder traffic during the harvest. The secondary skid trails are those that branch off from the primary trail.
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Skid trails are susceptible to erosion for several reasons. They are sometimes located on steep grades that drain quickly and concentrate water from the tract into a single channel. Skid trails generally contain exposed soil because the skidder churns up the leaf layer. Skidders can also rut the skid trail during wet weather, concentrating and channeling water. Finally, skid trails that are formed into the side of a hill with a bulldozer expose a large area of bare soil that is easily eroded. These skid trails are often referred to as "bladed" skid trails.
There are several precautions that can prevent erosion from skid trails during timber harvests. Grades of skid trails should be minimized by constructing trails along the contour of the land. Skid trail slopes of greater than 15% should be avoided. Water turnouts should be used to drain water from the skid trail along flatter sections. These turnouts are similar to those on your forest road. The logger can minimize the number of necessary skid trails by using longer winch cables. Loggers with special equipment, such as tracked skidders, may be able to continue operating during wet periods. However, loggers using conventional rubber-tired equipment should stop logging during wet weather in order to avoid deep rutting.
Log landings are the sites where logs are gathered and loaded onto log trucks. The size of log landings varies because of differences in terrain, tract size, timber type, and logging equipment. Log landings are potential erosion hazards because they expose a large area of bare soil.
The best way to prevent erosion from a log landing is to locate a good site. The soil of a log landing should be stable and well-drained. The landing should be located on a very slight slope (2-5%) to ensure drainage. Water runoff from the landing should be directed away from major channels and into a buffer where it can be slowed and filtered. Logging slash is sometimes placed below the landing to help slow runoff and minimize erosion. These practices can prevent major erosion from log landings in your forest.
"Close-down" requirements outline the conditions that should be established before the logger leaves the site. The most common close-down requirements are those in the Virginia BMP Technical Guide - specifically, seeding skid trails and landings, building water bars in skid trails, and cleaning up cans, oil containers, and other trash.
Water bars are angled humps in a skid trail that divert water from the skid trail into the litter layer, vegetation, a ditch, or some other structure. Water bars are similar to road dips, but are bigger because they are generally located on steeper grades. The BMP's recommend that water bars be constructed on the skid trail immediately after the logger has finished using that trail. The Virginia Department of Forestry has created recommendations for the distances between water bars. Your county forester will help you decide where water bars should be placed.
Skid trails and landings should be seeded with a mixture of grasses that are quick-growing and provide thick cover. Grass slows runoff from skid trails and landings, and roots hold soil in place. The objective of seeding is to provide cover on bare soils as soon as possible. Many timber sale contracts require the purchaser to seed the site in a timely manner, after the harvest is completed. The logger often handles this responsibility.
There are two important things you can do to influence how the logger operates. First, you can specify in the contract that the logger must follow Best Management Practices. The BMP's outline all the erosion control measures described in this handbook. Second, you can meet with the timber purchaser to review water quality issues from the contract.
During and after a logging job, you can check to ensure that the water quality standards outlined in the terms of your timber sale contract are followed. The county forester helps you with this task when performing logging inspections. One of the criteria of the VDOF's inspection relates to compliance with Best Management Practices. If the logging operation results in water pollution, the VDOF can recommend corrective action and stop the operation. If the recommended actions are not implemented, civil penalties can be assessed against the logger and landowner. The county forester may also look for other problems that may violate the standards in your logging contract.
Many landowners require timber buyers to provide a performance bond to ensure that BMP obligations are fulfilled. A performance bond is money that the purchaser gives a landowner to demonstrate the intention to fulfill the terms of the contract. The bond is deposited into the bank and is returned to the timber purchaser when logging is completed according to the contract. If the logging job does not meet contract standards, then the performance bond is used to pay for planting grass on landings and skid trails, repairing road damage, installing water bars, or performing other water management practices. Performance bonds simply serve as insurance that the purchaser will help you prevent damage to water quality.
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On A Side Note ...
Best Management Practices in a Typical Timber Sale There are several stages in implementing Best Management Practices (BMP's) during a timber harvest. Although your forester can perform most of the tasks associated with BMP's, it is a good idea for you to understand how they will be conducted. The major stages in BMP implementation include harvest layout and planning, marking the streamside management zone (SMZ), installing roads and water management structures, logging the timber, and closing down the harvest. This case study will describe the activities involved in planning and implementing BMP's in a typical timber sale. Layout and planning of the timber harvest is often considered the most important step in BMP implementation. When foresters begin the planning stage, they formulate strategies that will develop into a schedule of BMP activities. Much of the initial harvest planning will occur in the office. The forester and the logger work together to find the best locations for forest roads, log landings, and major skid trails. The forester also highlights sensitive areas, such as streams and fragile soils, that require special care. These features are often marked on a topographic map to pinpoint their exact locations. The second stage of BMP planning for a harvest is to locate and mark important features in the forest. The forester usually goes to the harvest area and marks these areas with paint or surveyor's flagging. Generally, the forester marks the boundaries of the harvest area, the SMZ's, the location of any roads, and a desired location for the log landing. Any other special areas such as steep slopes, springs and sinkholes, fragile soils, or cultural features will also be marked. These features are often marked with paint or flagging of different colors. For example, the boundaries may be marked with pink paint, the SMZ's marked with blue, and the roads and landing in yellow. When the harvest planning has been completed, construction of the road and logging areas can proceed. The most important duty of a landowner or forester is to assure that these structures are installed according to the standards in the harvest plan. The roads should follow the recommended route and should have all the designated drainage structures. The landings and main skid trails should be in designated locations and should meet the standards for slope and size. Close oversight of the installation of these features will help to clarify any misunderstandings before a feature is incorrectly established. When logging begins, the landowner or forester should regularly monitor the job to ensure that the BMP's are implemented. The logger should be observing streamside management zones and buffers around sensitive areas. Additionally, the weather and condition of the site are typically monitored. If the site becomes too wet to operate, logging operations should cease. Timber sale contracts should allow operation only when soil conditions are suitable in order to avoid damage to the site and water quality. When logging is completed on a particular site, it is important that the close-down activities are completed. In most situations, the logger is responsible for these activities. The landowner's role is to monitor the logger's work and check that activities are completed according to the standards in the harvest plan. For example, the landowner or forester needs to inspect the landing and skid trails to see that they have been graded, seeded, and that water bars have been installed as necessary. The road should be examined to ensure that it still meets the standards in the harvest plan. Finally, the county forester with the Virginia Department of Forestry is contacted to inspect the site for BMP compliance. |
Strategy #2: Prevent Runoff of Chemicals from your Forest
Pesticides and nutrients have long been recognized as pollutants of our water. Non-point sources of chemical pollution may be significant contributors to water quality problems in many areas. Nitrogen and phosphorus fertilizers are some of the most common non-point source pollutants, and are a far greater concern in agricultural areas than in the forest.
It is important to point out that these nutrients are important inputs to our forests. Trees must have a certain amount of each of these nutrients in order to survive. The problem arises when there are more nutrients in the system than the trees can use. In these cases, the extra nutrients often leach from the site and enter our streams.
In a sustainably managed forest, there is no need for fertilizers. The natural nutrient cycle is sufficient to meet the needs of most forests. Forest fertilization would be sustainable only in restoring a site to a more natural state. If fertilization is recommended in your forest management plan, you should question the purpose of the activity and consider more sustainable management alternatives.
We can minimize non-point source chemical pollution by not allowing pesticides and fertilizers to enter our streams and by slowing the runoff of nutrients that are already in the system. In a sustainable forest, natural nutrient loss through leaching or runoff is minimal. Specific management activities that you can perform in your forest include maintaining a streamside management zone, managing fertilization efforts carefully, contracting with reputable fertilizer and pesticide applicators, and requiring forest management contractors to maintain a clean job site.
A streamside management zone can reduce the runoff of fertilizer and pesticides into streams. Trees, bushes, and grasses filter nutrients from runoff, hence the term "filter strip." The SMZ is particularly successful in removing nutrients that are deficient in the soil. However, SMZ's are only marginally successful in removing large excesses of nutrients. Therefore, an SMZ is only the first step in managing chemical runoff.
The best width for the SMZ, relative to preventing runoff of fertilizers, depends on the concentration of nutrients in the water that drains through your forest. For example, if agricultural fields draining through your forest have been overly fertilized with nitrogen, then a wide SMZ might prevent excess nitrogen from entering the stream. If, however, the water that drains through your property is relatively chemical-free, then an SMZ of 50 feet would probably be sufficient. Your forester can help you determine how wide you should make your streamside management zone.
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An SMZ is most effective if you limit the management activities that occur within the buffer. Activities that could have the greatest impact on the ability of your buffer to filter chemical runoff are fertilization and pesticide application. Harvesting timber would also reduce the filtering capability of your SMZ because there would be fewer trees to remove nutrients. These issues should be addressed in your forest management plan. If you have any concerns about the impact of management activities within the SMZ, then it is best to prohibit activities in the area.
You should cautiously consider your options before deciding to fertilize your forest. Fertilization may provide results on some poor sites, but there is certainly an opportunity to apply the wrong fertilizer and place excessive chemicals into your forest. There are not very many fertilizers that are designed for application in hardwood forests, so your options are often very limited. Unless your forester recommends it, you should avoid fertilizing your forest.
You may choose the best fertilizer or pesticide for your forest, but improper application can still result in chemical runoff. A poor applicator may apply too much of the chemical, apply it unevenly, or apply the chemical outside your property. Fertilizer or pesticide might even be placed directly in a waterway, which certainly degrades water quality and is illegal in many cases. Therefore, it is important to select a contractor who will follow recommended application instructions.
There are several sources of information that can help you to choose among contractors. You can talk with your forester and other landowners who might have worked with the applicator on other properties. You can also investigate the licenses and registration of potential contractors - some are required by law to be licensed. Finally, you can meet with several contractors to look for a professional and responsible image. When you have completed these tasks, you can feel comfortable that you have chosen a contractor with a good reputation, image, and credentials.
When a forest management contractor such as a logger, herbicide applicator, or tree planter is working on your property, require that the job site be kept clean from trash and chemicals. In addition to making the job look better, you will be preventing chemicals from being spilled in your forest. In particular, you should investigate the contractor¼s waste management and equipment maintenance. The contractor should not leave containers that held oil, gas, pesticide, or other chemicals. Furthermore, the contractor should prevent equipment from leaking chemicals onto your site. It is a good idea to include a provision in your contract that pertains to waste management and equipment maintenance.
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On A Side Note ...
Special Features in the Water Supply: Karst Terrain Karst is composed of land that contains sinkholes, springs, and streams that drain into underground caverns and conduits. The caves and caverns in karst areas were formed over many years as limestone bedrock was dissolved by groundwater. Karst features are very important because they are a direct link to springs and wells from which we obtain drinking water. The caverns and caves in karst areas provide fragile habitats for many unique and rare creatures. Therefore, water quality is a vital issue in karst areas. If you have a property in western Virginia, then there is a good chance that you are linked to karst terrain. The most obvious way to determine if you are in a karst area is to look for springs, sinkholes, or caves. If you have any of these features in your forest, then it is located on karst terrain. If these features are found on a neighbor¼s property, then it is likely that your property is also connected to underground karst structures. There are several strategies for a forest landowner interested in preventing damage to water quality and karst features. A buffer of unmanaged forest should be established around streams, springs, sinkholes, and cave entrances. The buffer should be at least 50 feet wide, but a larger buffer would be more effective. Landings and skid trails should be positioned away from karst features and should not drain directly into the groundwater. Exposed soil can be seeded with quick-growing vegetation to prevent erosion of sediment into karst systems. Slash and other logging debris should not be placed near cave openings or sinkholes, where it can damage habitat and impede natural karst drainage processes. If karst features are abundant in your forest, you may want to talk with your forester about logging alternatives that are designed for minimal site impact. If you have a cave, sinkhole, or other karst feature in your forest, it is a good idea to contact your soil and water district, which is part of the Virginia Department of Conservation and Recreation (DCR). The DCR is active in the conservation of karst. Proper advice can help you make good management decisions concerning your karst forest. |
Strategy #3: Avoid Changing Water Temperature
Water temperature influences the type of aquatic life that will inhabit a stream. Temperature affects fish reproduction, growth, and development; concentrations of dissolved gases; and decay rates. Although every aquatic species has an optimal temperature, there is a larger range that it can tolerate. At extreme temperatures, the organism will die.
Forest management activities can damage the habitat for aquatic species by increasing the stream water temperature. In particular, humans affect stream temperature by removing the trees that shade it and by increasing the runoff of warm water into the stream. One of the best methods of preventing temperature changes in a forest stream is to maintain a streamside management zone.
An SMZ serves several purposes related to water temperature. It shades the stream from sunlight that can increase temperature. The SMZ slows runoff and allows it to soak into the groundwater, where it is cooled to a lower temperature. Establishing streamside management zones on tributaries can reduce the temperature of water entering your larger streams.
The best buffer width for maintaining stream temperature depends on topography, tree species and age, drainage, and other specific site characteristics. In general, if the trees close to the stream are sufficient to provide shade, then the buffer does not need to be very wide. Conversely, if the trees along the stream are short and do not provide shade for the stream, then a wider SMZ would be necessary to maintain temperature. A large buffer would be necessary to slow runoff from large and steep areas, but a smaller buffer would be sufficient for areas that are small and flat. A forester can answer questions about streamside management zones and stream temperature.
Strategy #4: Protect Sensitive Wetland Areas
A wetland is an area that is covered by water or has very wet soils that support wet-site plant species. Although they are relatively uncommon in western Virginia, wetlands are unique and sensitive areas that sometimes support rare habitats and species. Managers of sustainable forests must give special consideration to wetlands and should focus efforts on careful management of these special areas.
Several activities will help to protect wetland areas and should be considered in management planning. These activities include carefully reviewing laws pertaining to your wetland and developing a team of professionals to make management recommendations.
Several federal, state, and local laws relate to forest management in wetland areas. The most important of these is Section 404 of the Clean Water Act, which places restrictions on forest management activities in wetlands. The Clean Water Act specifically regulates mechanized land clearing and earthwork in wetlands, but some forest management activities are exempt from this law. It is wise to consult with your forester and the U.S. Army Corps of Engineers to determine if the Clean Water Act and other wetland laws pertain to your property. These laws should be addressed in your forest management plan. Because the laws are frequently updated, it is also a good idea to consult with the Corps of Engineers before performing any management activity in a wetland area.
When you are managing a forest located in a wetland, it is important to have good management advice. Your advisors should know the restrictions that apply to your property and be familiar with forest management practices that preserve wetlands. The county forester or consulting forester should be able to give you general advice and direct you to wetland experts.
Experts in several governmental agencies can help you manage a wetland. The Department of Forestry employs several forest engineers who specialize in road building and timber harvesting in wetlands. The VDOF engineer can help you determine if your wetland can be harvested and can make recommendations on how to protect the site. The U.S. Army Corps of Engineers is responsible for administering permits for forest management in wetlands regulated by the Clean Water Act. You should contact the Corps of Engineers before beginning any management activity in a wetland.
When you are performing forest management activities on wetlands, it is very important to work with a contractor who has wetland experience. Your forester can recommend qualified road builders, loggers, and tree planters. These contractors may be more expensive than regular contractors, but the added cost should be well worth the assurance of a job well done.
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