Authors: James A. Burger, Professor, Forestry and Soil Science, College of Natural Resources; and Carl E. Zipper, Extension Specialist, Crop and Soil Environmental Sciences; Virginia Tech
Publication Number 460-123, Revised 2002
Table of Contents
Introduction
Regulations and Performance Bonds
Selection, Placement, and Grading of Mine Soil Material
Tree-Compatible Ground Covers for Erosion Control
Tree Seeding Handling and Planting Techniques
Surface mining completely removes the forest. Public Law 95-87, the Surface Mining Control and Reclamation Act of 1977 (SMCRA), mandates that mined land be reclaimed and restored to its original use or a use of higher value. Restoring forests on surface-mined land is challenging; however, reforestation research by Virginia Tech's Powell River Project since 1980 shows that restored forests can be equally or more productive than the native forests removed by mining. In addition, reforestation can provide low-cost and timely release of reclamation bonds for coal miners, and restored forests can provide economic returns to landowners.
The purpose of this publication is to provide practical, cost-effective guidelines to ensure successful forestland reclamation using the principles of reforestation silviculture. The following guidelines were developed from research and practical experience; they should help reclamation managers and landowners achieve reforestation success and renewal of the many benefits that forests provide.
 Photo 1. 50-year old hardwood forest on mined land. |
 Photo 2. 16-year old pine forest on mined land. |
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The original forest of oaks, hickories, basswood, dogwood, maple, Fraser magnolia, cucumber tree and other mid- to late-successional species is not instantaneously restored. Instead, pioneer species such as leguminous trees and shrubs and pine and hardwood species that can tolerate a wide range of acidity, fertility, moisture, and temperature become established first. The pioneer species will eventually yield to the more site-sensitive hardwoods. In the meantime, the mine soil is being conditioned, nitrogen and organic matter are being incorporated, populations of macro and micro plants and animals are increasing, a more diverse wildlife habitat is being created, and valuable wood products are being produced. The rate at which natural forest succession proceeds depends on the nature of the reclaimed site and adjoining undisturbed sites. We believe it would require several hundred years for the mid- to late-successional hardwoods to dominate if forest restoration were left entirely to nature.
The reforestation procedures recommended below are designed to accelerate forest succession while providing land stabilization and erosion control, bond release for the mining operator, and economic returns to land owners. A combination of grasses, legumes, nurse shrubs and trees, and crop trees are established more or less simultaneously. Each plant type serves a specific reclamation function then yields to another plant type (Figure 1).
On sites reforested using these guidelines, hydroseeded grasses emerge first to quickly stabilize the mine soil surface. Grasses then yield to legumes when applied nitrogen is minimized. The slow-starting, ground-sprawling legumes allow trees to become established and grow before totally covering the ground. The legumes enrich the site and eventually give way to the tree cover. Nurse trees and shrubs condition the site for the crop trees and yield to the crop trees as they close canopy. This process of matching plant species to site conditions, matching plant species for their compatibility with each other in space and time, and managing tree stands to accomplish certain objectives as they develop, is called reforestation silviculture.
Figure 1. Reforestation silviculture seeks to stimulate natural processes known as forest succession. All vegetatation types are established during reclamation. As time passes, grasses and legume groundcovers yield to fast-growing pioneer species and nurse trees, which are themselves overtopped by commercially valuable crop trees as the forest grows and matures
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Although bond release requirements specified by state regulations (Coal Surface Mining Reclamation Regulations, Virginia Department of Mines, Minerals, and Energy, 1999) are similar for both commercial (managed) and unmanaged forest land, there are some subtle differences. Typically, unmanaged forest land is planted with white pine and various wildlife and nitrogen-fixing shrub and tree species. This species composition provides wildlife and environmental benefits with little or no management input after establishment and little or no long-term commercial value for the landowner.
The "commercial forest land" option provides an opportunity to use alternative reclamation practices to achieve a wood-production forestry management objective. For commercial forestry, a minimum stocking of 400 trees per acre of commercial species is required, in addition to 40 wildlife trees or shrubs per acre. As with any land-use designation, the coal company must submit a simple management plan that explains how the proposed postmining land use is to be achieved. Additionally, a copy of the comments by the landowner concerning the proposed use must be submitted. These documents are required to show that the landowner is committed to the proposed commercial forestland, and that it can be reasonably achieved.
The guidelines offered in this paper were developed to increase the probability of timely performance bond release as well as to ensure the establishment of productive forests. Regulatory requirements in this publication are specific to Virginia, but the general guidelines are applicable to reclamation in surrounding states. In Virginia, performance criteria for bond release can be achieved for forestland. Of particular importance are requirements relative to final surface grading, ground cover, and number of trees per acre.
Permitting
Successful reforestation, from a regulatory standpoint, starts with the mining permit. Regulatory authorities will reference the mining permit when judging reclamation success. Mine permitting for productive reforestation is discussed in Virginia Cooperative Extension Publication 460-141.
Final Surface Grading
In the past, establishment of smoothly-graded slopes with lush vegetation during the first year was a goal for many reclamationists. Unfortunately, land reclaimed in this way is often compacted by excessive grading, and the ground cover vegetation is too dense for tree establishment. Most southwest Virginia forested landscapes are uneven, and many are strewn with rocks and boulders. Natural forest soils are rough and loose, allowing deeply-rooted woody species to become established and grow unimpeded.
The Virginia Coal Surface Mining Control Reclamation Act of 1979 specifies that graded backfills "support the approved postmining land use." Compaction is only necessary "... where advisable to ensure stability..." (480-03 -19.816.102). Therefore, on level areas and short, gentle slopes, grading should be minimized to avoid surface soil compaction. After groundcover and tree establishment, small to medium gullies need not be filled unless they are associated with sedimentation problems or grow to the point where they would hinder forestry operations. Small to medium gullies may interfere with hayland/pasture uses, but do not interfere with forestry and wildlife habitat. Minesoil compaction resulting from gully repair is counterproductive to successful reforestation.
Ground Cover Establishment
Virginia regulations require ground cover to be at least 90 percent of the "success standard." The success standard depends on the designated post-mining land use. When trees are planted for "wildlife management, recreation, shelterbelts or forest uses other than commercial forest land," the success standard is 90 percent. This means that coal companies must achieve 81 percent cover, or 90 percent of the standard, for bond release. Ground cover for commercial forestland must be adequate to control erosion and achieve the specified land use.
Number of Trees per Acre
The number of trees per acre and species selection differs between commercial forestland and non-commercial forestland. For commercial forestland, there must be at least 400 commercial trees/acre plus 40 wildlife trees or shrubs (a minimum of 440 trees/acre) for bond release. In Virginia, white pine is a common commercial species. Mixed hardwood species are also considered commercial species. For non-commercial forest land, there must be at least 400 trees/acre, of which at least 40 must be wildlife trees or shrubs. Native invading trees count toward bond release if they are species suitable for the post-mining land use defined in the mining permit and at least one foot tall. Planting 550 crop trees and 60 to 100 wildlife or "nurse" trees per acre should achieve these required stocking densities, if soils and groundcover vegetation are compatible with tree establishment.
 Photo 3. Typical grading and tracking-in operations for non-forest post-mining land uses. |
 Photo 4. Example of uncompacted, roughly graded surface ideal for tree planting. |
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Trees have different mine soil requirements than forage grasses and legumes, both in terms of soil quality and depth. Most grasses and legumes can tolerate compacted surfaces, high pH levels, and high levels of soluble salts; trees cannot. Even if trees survive under these mine soil conditions, they will not grow well.
 Photo 5. Eight-year-old white pine growing in unweathered shale mine soil. |
 Photo 6. Eight-year-old white pine growing in weathered sandstone mine soil. |
 Photo 7. Cross-sections of 8-year-old white pine trees growing on shale (left) and sandstone (right) mine soils (grid line spacing 1 inch). |
Brown, oxidized sandstones, often found in deep layers near the land surface throughout the Appalachians, make the best mine soils for trees provided they are not pyritic. Research studies and many observations of reclaimed sites in Virginia, West Virginia, and Kentucky show that tree survival and long-term growth is excellent on oxidized, moderately-acid, sandstone-derived mine soils. Two parts brown, weathered sandstone and one part brown, weathered siltstone or shale have made an excellent topsoil substitute for trees in our research studies. In general, siltstone and shale that occur directly above or below coal seams should be avoided. These rock types usually have high levels of soluble salts, a high pH, and compact to greater densities when trafficked. Some of the white or blue-gray unweathered sandstones that occur further below the surface are acceptable for forest land. However, these spoils weather very slowly and should only be used when brown, weathered sandstone and siltstone are not available.
Mixing some fresh soil (where available) with overburden will improve the site's suitability for trees. Fresh topsoil typically harbors seeds and roots of tree and shrub species that can grow into viable seedlings when conditions are right.
Mixing some fresh soil into the surface will aid seedling survival, as beneficial fungi and microorganisms help seedlings obtain water and nutrients. In places where the soil handling cost makes it impractical to obtain large amounts of fresh soil for use in reclamation, even small amounts of soil (a truck load here and there, placed so it can be distributed during grading) will aid reforestation success.
Surface Grading
Reclaimed mine soils must be left loose and uncompacted to ensure successful establishment and long-term growth of trees. Prior to seeding ground covers, reclaimed sites are often cleared of large boulders, gullies are filled, and the surface is graded smooth and "tracked in" with bulldozers to create a seedbed for ground covers. This treatment is very undesirable for tree establishment and long-term forest growth. Powell River Project research shows that mine soil compaction is the single factor most limiting to reforestation success. When soils are excessively graded and tracked in, trees cannot be planted deeply enough. This results in poor survival and permanently reduces the mine soil quality. Compacted mine soils reduce water infiltration, reduce plant available water, increase sheet erosion, and restrict root growth.
When forest land is the post-mining land use, final grading should be limited to the extent needed to ensure the stability of slopes. On level and gently sloping areas, spoil placement should be planned so that once a pile is dumped in place, no more equipment passes over it except for a final, light grading. Mine soil compaction can be minimized by grading when mine soil materials are dry and using small dozers with low ground pressures. Natural forest land in the Appalachians is usually rougher than pastureland. Reclaimed forestland with boulders and uneven surfaces will not adversely affect forest management activities.
 Photo 8. Example of non-competitive, tree-compatible ground cover. |
 Photo 9. Example of competitive ground cover compromising the survival of trees. |
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A tree-compatible ground cover mix should include annual and perennial grasses and legumes. Because soil conditions typically differ across the site, species adapted to a variety of site conditions should be included within the mix.
Table 1.
Recommended groundcover seeding and fertilizer application rates for reforestation of reclaimed lands.
| Species/Fertilizer | Rate (lbs/acre) |
|---|---|
| Grasses: | |
| foxtail millet (spring seeding only) | 5 |
| annual ryegrass (fall seeding only) | 20 |
| red top | 5 |
| weeping lovegrass | 2 |
| perennial ryegrass | 10 |
| orchard grass (steep slopes only) | 5 |
| Legumes: | |
| kobe lespedeza | 5 |
| birdsfoot trefoil | 5 |
| ladino or white clover | 3 |
| Fertilizer*: | |
| nitrogen | 50 to 75 |
| phosphorus | 80 to 100 |
| * Blend 200 lbs/acre concentrated superphosphate with 300 lbs/acre 19-19-19 fertilizer or equivalent. | |
Annual grasses such as foxtail millet (Setaria italica), and annual ryegrass (Lolium multiflorum Lam.) provide quick, initial protection to the surface by reducing the impact of raindrops and minimizing soil movement. Foxtail millet is the preferred annual grass to use for spring or summer seeding; annual ryegrass should be used for fall seeding. These grasses germinate quickly and provide good cover during the first year. Since most annual grasses are tall, they must not be so dense as to adversely block light from seedlings. The limited shade and protection from wind provided by these annual grasses reduce seedling moisture stress. Annual rye and wheat grains should not be used in groundcover mixes for hardwood plantings. Their grain production attracts rodents that chew the bark of seedlings thus killing them.
After the first growing season, slower-growing perennial grasses and legumes should satisfy ground cover requirements. They should be adapted to low pH and fertility levels, and most grasses should be cool-season species to reduce competition with trees for moisture during mid summer. Perennial ground cover species should not grow so tall or dense that the establishment of trees is hindered. Perennial ryegrass (Lolium perenne) and redtop (Agrostis gigantea) are low-statured grasses that grow on relatively acid, infertile soils. They are quickly established and decline after several years, providing space for developing legumes.
On steep slopes, orchardgrass (Dactylis glomerata) can be included to provide additional protection against erosion. Kentucky-31 tall fescue (Festuca arundinacea, 'K-31') should not be used with trees. Kentucky-31 tall fescue competes excessively for light and moisture, it produces allelopathic substances (phytotoxic chemicals) that retard tree growth, and it attracts rodents that chew on the stems of trees.
Although weeping lovegrass (Eragrostis curvula) is a tall grass, it is a desirable component of a reforestation ground cover when used at low seeding rates (less than 2 lbs/acre). Weeping lovegrass is tolerant of very acid spoil and germinates within a few days, thus contributing to early erosion control.
A leguminous ground cover can enhance soil nitrogen (N) levels by as much as 50 lbs/acre/year. Legumes, in conjunction with Rhizobium bacteria, enhance the nitrogen status of the soil by fixing atmospheric nitrogen. Nitrogen released by decomposition of legume foliage and sloughed roots quickly becomes available to trees. Kobe lespedeza (Lespedeza striata var. Kobe) is a low-statured annual legume that should be included in reforestation ground-cover mixes. Kobe lespedeza reseeds itself very well and can persist for many years. Birdsfoot trefoil (Lotus corniculatus) is a perennial legume that has performed well in numerous research studies and on operational sites on mine soils in Virginia. The `Fergus' variety of birdsfoot trefoil is better adapted to Virginia than most of the northern varieties. Serecia lespedeza (Lespedeza cuneata) is not an acceptable legume; it is too tall and competitive, and it has become an invasive weed throughout the coalfields. Birdsfoot trefoil and white clover are a good combination since they are cool-season plants and are tolerant of moderately acid soils. This combination provides an actively-growing ground cover from spring through the fall season.
As a group, the clovers are less suitable for reforestation ground covers. Most clovers require soil pH and fertility levels that are higher than needed for trees, and most clover species are too aggressive during the first year to be used with trees. An exception is white or ladino clover (Trifolium repens); it is tolerant of acidic mine soils and produces a short cover that does not excessively compete with tree seedlings. It produces good cover for the first two years and then yields to the birdsfoot trefoil.
Importance of Using Tree-Compatible Ground Covers
Unlike standard hayland and pasture forages that are lush during the first year and gradually decline without additional fertilizer, tree-compatible covers are designed to be sparse during the first year and become increasingly dense by the second and third years. This allows tree seedlings to emerge above the ground cover and ensures their survival.
Despite relatively-low recommended seeding rates, 90 percent ground cover can be achieved for partial bond reduction during the first year. Most of the first-year cover results from the annual grasses, while the legumes dominate after several years. Birdsfoot trefoil and white clover emerge slowly by producing only a few plants per square foot, and these plants are generally less than six inches tall after the first season. By the third season, however, they develop into a complete cover replacing the grass and filling in under emerging trees. These legumes persist beneath the trees, increasing organic matter and nitrogen levels for several years until they are eventually shaded out by trees.
Another purpose of low ground cover seeding rates is to allow the invasion of native plant species such as yellow poplar, red maple, birch and other light-seeded trees. Dense ground covers prevent the natural seeding-in of native plants. An additional benefit of a tree-compatible cover is that some tree and shrub species can be established by direct seeding. When conventional ground covers are used, direct-seeded trees will not emerge and survive due to dense shading.
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Crop trees are long-lived species that offer value to landowners as saleable forest products. The most commonly planted pines are white, pitch x loblolly hybrids, and Virginia pines. Yellow-poplar (Liriodendron tulipifera), oaks (Quercus spp.), ash (Fraxinus spp.), maple (Acer spp.) and other hardwood species can also be planted as crop trees. Nurse trees are planted to assist the crop trees by enhancing the organic matter and nitrogen status of the soil and improving soil physical properties. Nurse trees will die or can be cut out after 15 to 20 years when crop trees need additional growing space. Nurse trees help achieve the minimum number of stems and ground cover required for bond release, and they provide food and cover for wildlife. Black locust (Robinia psuedoacacia) and autumn olive (Elaeagnus umbellata) were commonly used in the past, but are not recommended today. Other recommended nurse species are European black alder (Alnus glutinosa), bristly locust (Robinia fertilis), redbud (Cercis canadensis) and bicolor lespedeza (Lespedeza bicolor).
Crop Tree Selection
Pines.
On good sites, white pine can produce more merchantable volume than any other species. White pine on a 12 x 12 to 15 x 15 foot spacing (200-300 trees/acre) can produce merchantable timber in 30 to 40 years (Balmer and Williston, 1983). However, white pine requires higher-quality sites than other pines. White pine should be planted in areas that have at least four feet of uncompacted soil. It does best on deep, brown, well-drained, sandy mine soils.
On sites that are unsuitable for white pine due to depth, acidity, salinity, or drainage, other pine species should be planted. On shallow sites, or sites with a large amount of coal refuse, Virginia pine (Pinus virginiana) and loblolly pine (P. taeda) are good choices for crop trees. Both species are more drought-tolerant than white pine. Virginia pine is an excellent pulpwood species that is native to the region and is adapted to harsh sites. It has a shallow root system, which makes it a suitable species for shallow soils. It is also tolerant of acid mine soils with pH levels as low as 4.0. Loblolly pine is not native to the mountainous regions of Virginia, but it has been successfully planted and grown on many reclaimed sites. Some winter damage has been reported in the northern part of Virginia's coal mining region, but the problem seems to be no more severe than in the northern Piedmont of Virginia where loblolly pine is grown commercially. Good stands can produce pulpwood and sawtimber-sized trees in 20 to 40 years. Pitch x loblolly pine hybrid (P. rigida x taeda) may be the best commercially valuable pine species for planting on mine soils because of its tolerance to a variety of soil and site conditions and because of its rapid growth. It is a cross between loblolly and pitch pine, which is native to the region. It has the rapid growth rate and good form of loblolly pine, and the coldhardiness and strength of pitch pine. Loblolly pine, pitch x loblolly, and Virginia pine are more susceptible to damage by the southern pine beetle than white pine.
Photo 10. Northern red oak crop trees
on mined land after 55 years.
Hardwoods.
On well-constructed mine soils, most native hardwood species grow well. The critical factors that affect survival and growth of trees are spoil type, compaction, slope aspect and position, and competition from ground cover grasses and legumes. Ideally, these factors should be optimized during the reclamation process as described above. Most reclaimed sites, however, contain a variety of soil conditions. A key to successful reforestation with hardwoods is tailoring the species to mine soil conditions. Tree species can and should be selected to "fit" the final combination of conditions found on a reclaimed site. For example, hardwoods recommended for good sites are red, white, and black oak, tulip-poplar, sugar maple, black cherry, and white ash. Sycamore, green ash, and red maple are more tolerant of sites that are compacted, poorly drained, or have minesoils primarily derived from siltstones or shales (Figure 2).
Figure 2.
Tree species recommended for different spoil types and different levels of compaction.
Figure 3.
Tree species recommended for different slope aspects and positions.
Slope aspect and position (Figure 3) influence water availability through the growing season. The best sites for the most water-demanding trees and the most valuable species are slopes with a north and east aspect and a position toward the toe of the slope. Red oak, sugar maple, and tulip poplar are examples of species that should be planted on such sites. Southwest aspects toward the tops of slopes are the driest; therefore, drought-tolerant hardwoods such as scarlet and chestnut oaks should be planted in these positions. Good tree planting contractors can do site-specific tree selection and planting. Site-specific planting should be specified and described in mining permits and tree planting contracts.
Competition control of ground covers is also critical for reforestation success regardless of other conditions. Spot or row spraying with herbicides must be done when ground cover grasses are aggressive and competitive.
Many minesoils are excessively wet during much of the growing season because of poor internal drainage or because of compacted layers that perch water. Most high-value crop trees are intolerant of wet soils; however, sycamore (Platanus occidentalis), eastern cottonwood (Populus deltoides), and black alder grow well on wet sites and should be used under these conditions.
On very low-quality sites, with limitations due to compaction, acidity, or high soluble salt levels, the concept of selecting a long-term "crop tree" should be abandoned. Emphasis should be placed on stabilizing the site with trees and shrubs that are commonly used as nurse trees. As already mentioned, black alder is suitable for wet sites. Black alder and bristly locust are both tolerant of very acid sites.
Wildlife/Nurse Tree Selection
The nurse tree and nurse shrub species recommended for reclamation planting are N-fixing plants that benefit crop trees and provide food and cover for wildlife. Nurse trees contribute to ground cover requirements and help stabilize the site. Historically, black locust has been the most commonly planted nurse tree species in Virginia. Black locust is easily established and grows rapidly; unfortunately, it is very competitive and should not be planted with crop trees in a commercial forest mix. Black locust is too aggressive and the thorns on its branches can damage the branches and terminal leaders of adjacent trees. The best nurse tree for interplanting with most crop trees is European black alder. Black alder grows just as rapidly as black locust but it has no thorns. Black alder actually grows better than black locust on wet sites and very acid sites, and it provides a better source of food for wildlife.
Black alder should be used with a combination of shrub species (bicolor lespedeza, bristly locust) to enhance soil N levels and wildlife habitat. Bristly locust is especially well adapted to very acidic sites and should be used to a greater extent where erosion control is especially important. Bristly locust is a prolific sprouter; a single plant will develop into a large clump in several years.
Hydroseeding Trees
Some nurse species can be hydroseeded with the ground cover provided an appropriate ground cover mix is used. Many direct-seeding efforts have failed in the past because the accompanying ground cover was too tall and dense for tree germinants to become established. Black locust is most easily and inexpensively established by direct seeding. If black locust is seeded as a nurse tree, the seeding rate should be no more than 1/2 ounce per acre. A disadvantage of hydroseeding nurse trees is the loss of control with respect to tree number and spacing. Too many nurse trees can reduce the amount of growing space for crop trees, and wind-blown locust branches can damage the tops of trees growing in close proximity. Therefore, hydroseeding trees is not recommended for most mine land reclamation.
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Photo 11. Professional tree planting crew.
Assistance
Virginia residents can purchase a variety of tree species from the Virginia Department of Forestry (VDOF). Many species from the state nursery are grown from genetically superior seed and should perform better than other seed sources on Virginia mine soils. If planting is managed directly by coal companies, supervisors should work carefully with their local VDOF forester in ordering and picking up seedlings. A common reason for poor seedling survival in Virginia is that planting crews pick up more seedlings than they can reasonably plant within a short period of time. If planting crews cannot keep seedlings in cold storage until planting, they should arrange with the VDOF to pick up a smaller number of seedlings on a more frequent basis.
Use Healthy Seedlings
Seedlings should be graded prior to planting so that only healthy seedlings are used. Healthy pine seedlings should have a root collar diameter of 4/32 to 9/32 inches. Very small pine seedlings (under 4/32 inches diameter) and very large seedlings (over 10/32 inches in diameter) do not survive well. Very large seedlings are difficult to plant correctly. Root pruning is not recommended; there is a tendency to chop off too much of the root system. With root pruning now being done in the nursery beds, none is needed at the planting site. Overall survival is better when no root pruning is done by tree planters. Seedlings should not be planted if the roots are dry. Air-dried roots have less growth potential than roots that remain moist.
Seedling Storage
Proper seedling storage and handling before planting is critical to ensure good survival and growth. Seedlings must not be allowed to get hot or dry. If planting is delayed, the bags of seedlings should be wetted and roots dipped in a moisture-retaining gel specifically designed to keep roots from drying. The seedlings should then be rebundled and placed in cold storage (32-36° F) for no more than four weeks. If cold storage is not possible, they should be stored in a cool damp basement for no more than a week. At temperatures over 40°F, mold develops and seedlings are killed. Without cold storage, it becomes more important to dampen the roots as soon as they are delivered.
Tree Planting
 Photo 12. Proper storage and handling of seedlings is critical to reforestation success. |  Photo 13. Roots of seedlings must be kept moist prior to planting. |
 Photo 14. Seedlings must be planted properly in order to survive. |
Seedlings should be planted as soon as possible in late winter or early spring (February-April) after the ground has thawed. Early planting is preferred because the soil is usually wetter and more conducive to root growth. Root growth decreases during periods of rapid shoot elongation; therefore, it is important that the seedlings be planted early in the season so roots can become established before the weather turns warm enough for shoot growth to begin. During planting, crew leaders need to make certain that planters do not expose roots to the air by carrying seedlings in their hand. Seedlings should be carried in a planting bag and not removed until the planting hole is opened. Planting holes must be opened deeply enough so that the roots can be evenly spread in the hole. Seedlings should be planted about one inch deeper than grown in the nursery. Finally, the planting hole must be completely closed since any air spaces around the roots will cause those roots to die.
Supervision
Planting crews should be given instructions on proper techniques prior to planting, and crew leaders should start quality checks immediately so that needed corrections can be made before much of the area is planted. The VDOF will do planting-quality checks for landowners or operators who want to verify and/or improve seedling survival. This involves careful lifting of planted seedlings on random plots to check on seedling health, tightness, depth of planting, straightness, spacing, and density. Seedlings are carefully replaced after each one is inspected.
Establishing Trees in Dense Ground Cover
Sometimes it is necessary to establish trees in an existing cover of dense grasses or legumes such as K-31 tall fescue or Serecia lespedeza. In order to ensure survival and good growth, herbicides and slow-release fertilizer pellets are highly recommended. Chemical weed control (herbicides applied via backpack sprayer) helps maintain the seedlings free of overtopping competition. By controlling dense vegetation with herbicides, seedlings will receive adequate sunlight and more soil water to ensure their survival. In conjunction with weed control, slow-release fertilizer pellets can speed growth during the first few years to help the trees grow above surrounding grasses. Fertilizer pellets should be placed in the closing hole about two inches from the roots during planting. Fertilizer pellets slowly decompose and release nutrients needed by the trees. By using pellets it is possible to selectively fertilize seedlings without fertilizing surrounding grasses.
Herbicide technology changes rapidly. New chemicals appear on the market annually and herbicide labels and regulations change almost as quickly. For these reasons, a timely discussion of best herbicide treatments is not possible. Contact your local VDOF forester or county extension agent for current recommendations of specific herbicide products and application rates.
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Coal companies doing reforestation should be able to realize additional costs savings on regrading costs since gully elimination requirements for forest land are not as strict as for hayland/pasture; we have estimated that savings at about $75 per acre. Seed and fertilizer for the tree-compatible ground cover (Table 1) costs about $50/acre less than hayland/pasture seed mixtures with high rates of K-31, clovers and other species.
Forest land reclamation does involve tree planting costs. Planting 600 trees/acre will cost about $200/acre. If compaction has been avoided by reduced grading, and a tree-compatible ground cover is used, a sufficient number of trees will become established through the combination of planting and natural invasion to satisfy bond release requirements and result in a well-stocked forest.
Benefits of Quality Reforestation
Studies on the Powell River Project show that mine soils covering a wide range of quality have been constructed by mining operations under SMCRA. This productivity spectrum is represented by sites on which trees are unable to survive, to sites on which trees are growing at rates faster than on natural, undisturbed soils (Torbert et al., 1988). In forestry, soil or site quality is measured using a "site index" defined as the average height of the tallest trees in the stand at age 50. The data in Table 3 compare the projected heights of 50-year-old white pines on three reclaimed sites having different site qualities due to different mine soil depths. Projected tree heights on the three sites with mine soil depths of 12, 24, and 48 inches are 60, 80, and 100 feet, respectively, at age 50. These site indices correspond to poor, good, and excellent for white pine in this region, since a site index of 80 is average for undisturbed soils in the southern Appalachians.
Table 2.
Relative costs for hayland/pasture and forest land reclamation.
| Operation | Hayland/Pasture ($/ac) | Forest Land ($/ac) |
|---|---|---|
| Grading cost difference | 360 | --- |
| Gully repair | 75 | --- |
| Seed cost difference | 50 | --- |
| Re-seeding | 125 | --- |
| Tree planting | --- | 300 |
| Total | 610 | 300 |
Table 4.
White pine growth and value by age 30 on mine soils of different depths and qualities.
| Mine Soil Depth1 (inches) | Site Index 502 (ft.) | Standing Timber Volume at Age 303 (MBF/acre) | Wood Products | Harvest Price ($/MBF) | Total Value ($/acre) |
|---|---|---|---|---|---|
| 12 | 60 | 5 | mine props/pulp | 20 | 122 |
| 24 | 80 | 14 | small sawtimber | 50 | 1,755 |
| 48 | 100 | 32 | large sawtimber | 75 | 3,480 |
| 1 Torbert et al., 1988 2 Site Index50 = height of tallest trees at age 50. 3 Thousand board feet (MBF); from Balmer and Williston, 1983. |
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An excellent mine soil able to produce white pines that are 100 ft tall at age 50, versus a poor mine soil producing 60-ft-tall trees, represents a very large difference in the amount and quality of wood produced (Table 3). When reclaimed properly, mine soils can produce a harvestable tree stand in 35 years with six times more board-foot volume than that produced on a poor quality site. Because larger trees have more valuable wood due to the higher-value use to which the wood can be put, the product value can be many times greater ($3,480 versus $122) on the excellent site compared to that of the poor site. Hardwoods respond to mine soil quality in the same way. Hardwoods growing on poor sites have virtually no commercial value, while timber value of hardwoods on good sites can be as much or more than that on non-mined sites (see VCE Publication 460-138). Just as the value of a corn crop or hay crop is used to judge reclamation success for cropland or grassland, the potential of a reclaimed site to produce wood of high value should be the standard used to judge mine soil quality for reforestation.
Restoring economically viable, post-mining forests requires little or no additional effort or expense, compared to other common post-mining land uses such as hayland or pasture. If reclamation procedures are specifically geared for reforestation, highly productive forests can be created in a timely manner so that the mine operator, the landowner, and the community at large will benefit. As the regional economy diversifies from its traditional coal base, communities will be able to turn toward the restored forest as a valuable, renewable resource in which to live, recreate, and use for income.
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Reclamation procedures for forest land differ in several important ways from procedures for hayland/pasture or other post-mining land uses. The key principles for timely and successful reforestation of mined land are summarized below.
Mine Soil Material
Spoil selection.
In addition to available topsoil, four feet of a good-quality mine spoil should be placed at the surface to accommodate the need of deeply rooted trees. Mine spoils with low to moderate levels of soluble salts, an equilibrium pH of 4.5 to 6.5, and a sandy loam texture are preferred. A mixture of two parts of brown, oxidized sandstone, and one part of brown, oxidized shale, found near the surface in most areas of Virginia's coal fields, weathers quickly into a good soil medium for trees. If native topsoil is available, mixing even small amounts of fresh soil into the surface will increase volunteer establishment and seedling survival.
Grading.
Minimizing soil compaction is extremely important. Compaction on level areas can be minimized by end dumping spoil piles and waiting until all piles are in place before lightly leveling them, using a small bulldozer if possible (see VCE Publication 460-136). Restrict traffic on leveled areas to specific, designated roads and parking areas. Do not track-in level areas, slopes less than 20 percent, and slopes less than 100 feet long. Forest land surfaces are naturally rough; rough grading and grading for slope stability are usually adequate.
Ground Cover Vegetation
Tree-compatible groundcover.
Reforestation requires a carefully-planned balance between ground cover for erosion control and trees' requirements for light, water and space. Ground covers should include grass and legume species that are slow-growing, have a sprawling growth form, and are tolerant of acid, infertile minesoils. K-31 tall fescue and all clovers (except white and ladino) should be avoided.
Tree Establishment
Tree species selection.
When mined land is reclaimed according to these guidelines, a variety of hardwood and softwood species can be planted and established successfully. Pioneer species such as nitrogen-fixing trees and shrubs are easily established by planting seedlings. Additional hardwood species from the native forest will eventually seed in and flourish when proper groundcovers and woody species are planted during reclamation (see VCE Publication 460-140). For good forest stand development, 600 to 700 trees per acre should be established by a combination of planting, seeding, and natural invasion.
Seedling handling and planting techniques.
Poor tree survival and early growth are usually due to improper seedling handling or planting. Trees must be kept dormant until planted; they should never be allowed to dry out; they should be planted in late winter to early spring; and they should be planted deeply and firmly enough to ensure survival. Help and advice on seedling handling and planting can be obtained from a Virginia Department of Forestry (VDOF) forester or county extension agent. Only reputable and experienced tree planting crews should be used for tree planting.
Hydroseeding trees.
To reduce the expense of hand planting, some nurse tree species (e.g. bristly locust, black alder, redbud, etc.) under certain conditions can be established by direct seeding provided a tree-compatible ground cover is used. However, planting seedlings is recommended to ensure survival and proper tree spacing and stand composition.
Establishing trees in dense ground cover.
Herbicide should be sprayed in spots or strips (along the contour) in order to ensure seedling survival and emergence above established ground covers. Fertilizer pellets can be placed in the planting bar closing hole (never in the planting hole) to speed early growth and emergence above ground covers. Loblolly and Virginia pines are especially fast growing and responsive to fertilization. Herbicide technology changes rapidly; contact a VDOF forester or county extension agent for herbicide recommendations.
Costs and Benefits
Costs of reforestation.
Reclaiming mined land with trees can be less expensive than reclamation for hayland/pasture use. Planting 600 trees/acre of higher quality hardwoods and wildlife/nurse species will cost about $200/acre (2002 estimates). Reclamation with trees is cheaper than reclamation for hayland/pasture land uses because forest land reclamation requires less grading, less repair work, and less seed and fertilizer for ground covers (estimated savings = $300). The extensive grading required for hayland/pasture reclamation compacts mine soils which decreases tree survival and growth. Rougher ground surfaces and less aggressive ground covers are consistent with forest land uses.
Mine soil quality.
High-quality, productive mine soils are as important for forest production as for crop or forage production. Deep, uncompacted mine soil with good physical and chemical properties are absolutely required for commercial timber production. When mine soils are capable of producing high wood volumes, other forest values such as wildlife habitat, water quality, and recreational opportunities are also maximized.
Restoring economically-viable post-mining forests requires little or no additional effort or expense compared to other land uses. Use of the reclamation procedures outlined in this publication will help create highly-productive forests in a timely manner so that the mine operator, the landowner, and local communities will benefit.
Acknowledgements and Photo Credits
Photos 3 and 7 by John Torbert.
Photos 4, 9, 11, 12, 13, and 14 by Rick Williams all other photos by Jim Burger.
Our thanks to the many mining firms and individuals who have worked with Powell River Project to aid reforestation research and application of research results, including Pocahontas Land Corporation, Pittston Coal, Rapoca Energy, and Red River Coal.
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Maximizing the value of forests on reclaimed mined land. J.A. Burger, Dan Kelting, and C. Zipper. Publication 460-138. http://www.ext.vt.edu/pubs/mines/460-138/460-138.html
Recovery of native plant communities after mining. Karen D. Holl, Carl E. Zipper, James A. Burger. Publication 460-140. http://www.ext.vt.edu/pubs/mines/460-140/460-140.html
Mine Permitting to Establish Productive Forests as Post-Mining Land Uses. J. Burger, C. Zipper, and J. Rodrigue Publication 460-141. http://www.ext.vt.edu/pubs/mines/460-141/460-141.html
Research Articles
Ashby, W. C., W. G. Vogel, C. A. Kolar, and G. R. Philo. 1984. Productivity of stony soils on strip mines. p. 31-44. In: Erosion and Productivity of Soils Containing Rock Fragments. Soil Sci. Soc. Am. Special Pub. No. 13.Madison, WI. 103 pp.
Balmer and Williston. 1983. Managing eastern white pine in the southeast. USDA For. Ser. Rep. R8-FR1. 11 pp.
Beck, D. E. 1971. Growth intercept as an indicator of site index in natural stands of white pine in southern Appalachians. USDA For. Res. Note SE-154.
Burger, J. A., and J. L. Torbert. 1990. Mined land reclamation for wood production in the Appalachian region. p. 159-163 In: Proc., 1990 Mining and Reclamation Conference and Exhibition. Charleston, WV. National Meeting, American Society for Surface Mining and Reclamation.
Preve, R. E. 1983. hydroseeding pine-grass-legume mixture for erosion control and reforestation of mine spoils. M.S. Thesis, Dept. of Forestry, Virginia Polytechnic Institute and State University, Blacksburg.
Preve, R. E., J. A. Burger, and R. E. Kreh. 1984. The influence of mine-spoil type, fertilizer, and mycorrhizae on pines seeded in greenhouse trays. Journal of Environmental Quality 13:387-391.
Schoenholtz, S. H., and J. A. Burger. 1984. Influence of cultural treatments on survival and growth of pines on strip-mined sites. Reclamation and Revegetation Research 3:223-237.
Schoenholtz, S. H., J. A. Burger, and J. L. Torbert. 1987. Natural mycorrhizal colonization of pines on reclaimed surface mines in Virginia. Journal of Environmental Quality 16(2):143-146.
Torbert, J. L., J. A. Burger, J. N. Lien, and S. H. Schoenholtz. 1985. Results of a tree species trial on a recontoured surface mine in southwestern
Virginia. Southern Journal of Applied Forestry 9:150-153.
Torbert, J. L., J. A. Burger, and W. L. Daniels. 1986. Effect of overburden type and Pisolithus tinctorius on the growth of pines on a reclaimed surface mine. In: Proc., Better Reclamation with Trees Symposium.
Torbert, J. L., J. A. Burger, and W. L. Daniels. 1986. The importance of overburden selection for reforestation of mine spoils. Virginia Cooperative Extension Pub. 460-111.
Torbert, J. L., J. A. Burger, and R. E. Kreh. 1986. Nutrient concentration effects on Pisolithus tinctorius development on containerized loblolly pine (Pinus taeda L.) seedlings. Tree Planters' Notes 3 7:17-22.
Torbert, J. L., T. Probert, J. A. Burger, and R. Gallimore. 1989. Creating productive forests on surface mined land. Green Lands 19(4):28-31.
Torbert, J. L., J. A. Burger, T. J. Nichols, and J. E. Johnson. 1989. Growing Christmas trees on surface mined lands. Virginia Cooperative Extension Publication 460-116.
Torbert, J. L., J. A. Burger, and W. L. Daniels. 1990. Pine growth variation with overburden rock type on a reclaimed surface mine in Virginia. Journal of Environmental Quality 19:88-92.
Torbert, J. L. and J. A. Burger. 1990. Tree survival and growth on graded and ungraded minesoil. Tree Planters' Notes 41(2)3-5.
Torbert, J. L., A. R. Tuladhar, J. A. Burger and J. C. Bell. 1988. Minesoil property effects on the height of ten-year-old white pine. Journal of Environmental Quality 17:189-192.
Torbert, J. L., J. A. Burger, S. H. Schoenholtz, and R. E. Kreh. 2000. Growth of three pins species after eleven years on reclaimed minesoils in Virginia. N. J. Appl. For. 17: 1-5.
Torbert, J. L., and J. A. Burger. 2000. Forest land reclamation. p. 371-398. In: R. I. Barnhisel, R. G. Darmody, and W. L. Daniels (ed.). Reclamation of Drastically Disturbed Lands. Agronomy No. 41. American Society of Agronomy, Madison, Wisconsin.
Vogel, W. G. 1981. A guide for revegetating coal minesoils in the eastern United States. USDA For. Serv. Gen. Tech. Rep. NE-68. 190 pp.
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