Longleaf pine in Mississippi occupies some 255,000 acres in the southeastern part of the state. The acreage represents almost a 90-percent decrease from an estimated 2.1 million acres in 1935. Perry, Forrest, and Lamar counties have the most acres of longleaf pine in Mississippi, accounting for almost half of the longleaf acres in the state.
Compared to other longleaf-producing states, Mississippi has the greatest percentage of longleaf pine sites classified as "superior quality."1 This is due to suitable climate, topography, and soils. More than 75 percent of Mississippi's longleaf pine sites are superior quality, whereas only 15 percent of longleaf sites outside Mississippi are superior. Longleaf pine's scientific name, Pinus palustris, refers to the wet coastal sites where longleaf was first discovered; "palus" is Latin for "marsh."
For economic, aesthetic, and other reasons, Mississippi landowners are becoming increasingly interested in restoring longleaf pine to those sites where it originally grew. This offers a greater challenge than regenerating loblolly or slash pines because of the exacting conditions required by longleaf. This publication focuses on factors that led to longleaf's decline, reasons for the renewed interest in longleaf, and landowner options in regenerating longleaf pine.
A sense of urgency exists for those interested in regenerating longleaf pine. Two-thirds of Mississippi's longleaf pines are sawtimber size and approaching maturity. Longleaf's decline will continue unless landowners manage for regeneration.
1Superior sites are capable of producing at least 85 cubic feet per year when fully stocked; medium sites produce 50 to 84 cubic feet per acre per year, and low sites produce 20 to 49 cubic feet per acre annually.
Longleaf pine forests originally covered more than 60 million acres, extending along the Coastal Plain from southern Virginia to eastern Texas, in the Piedmont of Alabama and Georgia, and in the Ridge and Valley of Alabama. Some estimates run as high as 90 million acres, although these acres include mixtures of longleaf pine and other species.
Virgin stands present when European explorers arrived contained an estimated 200 billion board feet. For more than 250 years following European settlement of Virginia, human impact on the longleaf forest was minor and limited to Virginia, North Carolina, and the major river courses.
From early settlement until about 1900, mills consisted mostly of small tidewater operations along coastal areas. This period witnessed relatively minor impacts on the longleaf pine forest. The vast interior longleaf forest was still intact. Events in the late 1800s greatly accelerated the longleaf harvest. Locomotives specifically designed for logging increased accessibility, steam skidders increased the number of logs that could be hauled, and new band saws increased milling capacity tenfold.
The period between 1900 and1930 witnessed the establishment of large inland mills and some of the most intensive forest liquidation the world had ever seen. Some refer to this period as the "railroad logging era." The longleaf pine harvest peaked in 1909, and by 1935 the once vast longleaf forest was reduced to one-third of its original size, or about 20 million acres. Only 1.6 percent of the remaining acres were classified as uncut old growth, and 7.5 percent of the acres were classified as partially cut old growth.
After 1930, the species continued its drastic decline due to the clearing of land for agriculture and development, regeneration failures, and replacement by more aggressive and faster growing loblolly and slash pines. Data from 1995 show only 3 million acres of longleaf remaining, which is less than 5 percent of its original extent.
From the start, longleaf pine forests were harvested for a variety of products. Historically, beneficial uses focused on lumber, pulp, and naval stores. Because of its tall, straight form, longleaf was used as masts for sailing ships and was exported to other countries. Domestic use was vast and supported the growth of a new nation. Naval stores, principally turpentine and rosin from resins taken from living trees, peaked in the early 1900s then declined as the virgin longleaf disappeared; these materials became by-products of the pulp and paper industry.
Longleaf pine has potential financial advantages over loblolly and slash pines, particularly in sawtimber-length rotations. Longleaf pine's primary economic advantage is that its tall, straight, knot-free form is ideal for producing high-valued poles, which are worth 30 to 40 percent more than sawtimber. Longleaf pine stands usually produce a much greater percentage of poles than do the other pine species. One survey shows almost two-thirds of longleaf pine sawtimber-sized trees could be sold as poles, whereas only one-quarter of the slash pine sawtimber-sized trees made poles. The percentage of loblolly pine making poles is even less.
An additional benefit of longleaf pine is that more landowners are interested in planting species native to the site, and for most upland sites in south Mississippi, longleaf pine is the native species. Also, longleaf is more resistant than loblolly or slash pine to insects such as the southern pine beetle and diseases such as annosus root rot and fusiform rust.
Initial regeneration efforts with longleaf often failed because foresters and landowners did not realize its regeneration is different from other pines. First, upon germination, longleaf pine seedlings enter what is termed a "grass stage," where it can persist like a clump of grass for up to 10 years or longer before starting height growth. Hardwood brush and herbaceous weeds are able to grow over and outcompete the seedlings for moisture and sunlight, retarding height growth and often killing seedlings. For landowners interested in short-rotation timber production, this grass stage is a distinct disadvantage.
A second factor that inhibits regeneration is that longleaf pine, in the grass stage, is susceptible to brown spot disease, a fungus that reduces seedling vigor and can kill seedlings. A third problem was poor planting-stock quality in artificial regeneration. Complete failures of longleaf pine plantings were common. It was not recognized that planting and growing longleaf pine seedlings correctly were more difficult than with slash and loblolly pines.
Fourth, where natural regeneration was attempted, there often were too few mature trees left after logging to adequately seed an area. Longleaf pine seed are larger and heavier than other pines, and the seed fall close to the parent tree. The combination of too few seed trees, heavy seed, and infrequent seed crops has produced many understocked stands that persist to this day.
Other factors inhibiting longleaf regeneration include free-ranging hogs that eat young seedlings and the lack of fire to prepare a seedbed, reduce competition, and reduce the incidence of brown spot disease. The latter has led to much natural encroachment of loblolly and slash pines onto longleaf sites.
Most of these limitations described have been overcome or minimized; this fact, combined with longleaf's high economic value, has generated much of the current interest in longleaf. Successful techniques for regenerating longleaf pine by artificial and natural means have been developed. With proper treatment, the grass stage is greatly reduced, and the tree can grow nearly as rapidly as the other pine species on most sites and better on some.
Planting stock for longleaf is produced in two ways: as bare root or seedlings grown in containers. Bare-root seedlings are those grown in a plant nursery, then removed (lifted) for processing, shipping, and planting. The bare-root seedling is just that--a tree seedling with minimal soil attached to the roots. This makes it less expensive and easier to handle in bulk. The lifting process, however, divides part of the root system and can severely stress seedlings if too many roots are removed. Compounded by poor handling and planting, stress can greatly reduce bare-root survival rates compared to those of seedlings grown in containers.
Seedlings in containers are grown individually; the soil mass and plant are planted together. Because the root mass remains intact and relatively undisturbed from germination until planting, there is less damage to the root system and less stress upon the seedlings. Compared to bare-root seedlings, seedlings in containers generally survive better, move through the grass stage more rapidly, and enable landowners to plant later into the spring season. Even though seedlings in containers cost about three times more than bare-root seedlings, the assurance of a good stand of longleaf is often worth the cost.
As mentioned, many earlier plantings with longleaf pine bare-root seedlings were unsuccessful because the importance of seedling quality and proper planting technique were not recognized. High-quality bare-root seedlings properly planted on sites free from woody or herbaceous plant competition increase survival rates, allow the seedlings to move rapidly through the grass stage, and promote rapid height growth. High-quality longleaf seedlings have a root collar diameter (RCD) of 0.4 inch, an 8-inch-long taproot, and many lateral roots.
Plant the seedling as soon after lifting as possible. Planting dates extend from mid-December to mid-February in Mississippi, but earlier plantings generally have better survival rates. If the seedlings cannot be planted immediately, refrigerate them to reduce mortality. Plant the seedling with the root collar slightly below the soil surface to protect it from cold temperatures, and avoid planting in periods of climatic stress (low soil moisture, high winds, low temperatures).
Control competing woody and herbaceous vegetation before planting and for at least 2 years following planting. Focus on having 300 to 500 live seedlings per acre a year after planting. Consulting successful longleaf plantations for guidance can save time, effort, and money.
As a stand approaches maturity, thin the stand to medium density, leaving the best trees. This opens up the stand, promotes crown development, and leaves the best parent trees. This cut is a "shelterwood preparatory cut" because it prepares the stand for the future.
Table 1 shows the number of trees per acre to leave after the preparatory cut. After about 5 years, reduce the number of trees even further, leaving the final seed trees. This is called the shelterwood seed cut, and the stand at this point should appear open. It is important to leave about 30 square feet of basal area per acre of the best-formed and best seed-producing trees after the seed cut. This cut provides good genetic stock and maximizes seed production, yet it allows enough light for seedlings to begin growth. Table 1 also shows the number of trees per acre to leave after the seed cut.
Because longleaf pine is an irregular seed producer, it is important to time treatments to coincide with a good seed crop. To forecast seed crops in the spring, use binoculars to count conelets. Roughly 1,000 cones per acre, or 35 to 50 cones per seed tree, generally are needed to establish an adequate number of seedlings.
Seed fall primarily in late October to early November, germinate quickly, but cannot penetrate a thick layer of litter or grass. Conducting a prescribed fire or light scarification 3 to 10 months before seed fall prepares a good seedbed and enhances seedling survival. A burn conducted too close to seed fall, however, leaves the ground open, and birds, rodents, and other animals can find and may eat much of the seed crop, unless it is a bumper crop.
Longleaf does not compete well with other vegetation. Controlling hardwoods and herbaceous weeds with fire or herbicides (or both) before and after the seed cut enhances survival and growth of germinated seedlings. By reducing competing plants, more water is also available to seedlings, which is particularly important on sandy sites where water percolates rapidly through the soil profile.
Once an adequate number of seedlings (about 6,000 per acre) are established, remove the parent seed trees when seedlings are 1 to 2 years old. Having this number of seedlings ensures enough survivors after harvesting the overstory. Delaying the harvest of parent trees increases seedling mortality.
Longleaf pine is a fire-dependent species, which means that fire helps create those conditions required by longleaf to naturally regenerate. It is not immune to fire, however, and seedlings less than a year old and seedlings just out of the grass stage are particularly vulnerable to fire.
Prescribed burning prepares a seedbed by exposing mineral soil and reducing competition from woody and herbaceous species, thus aiding in regeneration. In seedling stands, proper burning reduces the amount of brown spot fungus infection. In heavily infected stands, however, the infected needles become a fuel source instead of protecting the bud from the heat of the fire.
Burning seedlings under a parent stand is risky and, if necessary, must be done carefully to preserve the seedling stand. The fire must be properly prescribed and controlled or all seedlings beneath the crowns of the parent trees can be lost largely due to high needle fuel loads located there.
To keep competing vegetation in check, prescribed burning is probably best done on about a 3-year cycle, from the sapling stage through maturity. Winter burns are easier to apply, but a series of spring burns may sometimes be required.
Prescribed burning also benefits a variety of wildlife species. Longleaf pine forests have a natural high diversity of understory species, and prescribed burning maintains the open understory and diversity of plant species critical to wildlife as food. Ground-dwelling wildlife such as deer, turkey, rabbits, and bobwhite quail benefit from proper burning. The vast majority of mammals found in longleaf forests feed on the ground. The lack of fire results in woody vegetation developing and shading out the important understory species, which reduces wildlife habitat quality.
Landowners have access to knowledge and techniques to largely overcome factors that limit initial reforestation efforts with longleaf pine. With the existing markets, sites, and regeneration options, longleaf pine is a species that owners of forestland in southeast Mississippi should seriously consider.
Boyer, W. D. 1996. Anticipating good longleaf pine cone crops. Alabama's TREASURED Forests (15:24-26).
Crocker, T .C. Jr. 1987. Longleaf pine: A history of man and a forest. USDA Forest Service Forestry Report R8-FR7 (37 pp.).
Dennington, R. W., and R. M. Farrar. 1983. Longleaf pine management. USDA Forest Service Forestry Report R8-FR 3 (17 pp.).
Dennington, R. W. 1990. Regenerating longleaf pine with the shelterwood method. USDA Forest Service Management Bulletin R8-MB 47 (2 pp.).
Franklin, R. M. 1997. Stewardship of longleaf pine forests: A guide for landowners. Longleaf Alliance Report No. 2 (41 pp.). The Longleaf Alliance, Solon Dixon Forestry Education Center, Andalusia, Alabama.
Landers, J. L., D. H. Van Lear, and W. D. Boyer. 1995. The longleaf pine forests of the southeast: Requiem or renaissance? Journal of Forestry 93:39-44.
Vanderveer, H. L. 1993. When to use containerized seedlings. Forest Farmer 52:17-19, 36.
Walhenberg, W. G. 1946. Longleaf pine: Its use, ecology, regeneration, protection, growth, and management. (429 pp.). Charles Lathrop Park Forestry Foundation, Washington, DC.
Hermann, S. M. (1993). The Tall Timbers Fire Ecology Conference, No. 18. (418 pp.). The longleaf pine ecosystem: Ecology, restoration, and management. Tall Timbers Research Station, Tallahassee, Florida.
Kush, J. S. (1996). First Longleaf Alliance Conference. Longleaf pine: A regional perspective of challenges and opportunities. Longleaf Alliance Report No. 1 (178 pp.).
|Tree Guide for Natural Regeneration of Longleaf Pine|
Per Acre Preparatory Cut
Per Acre Seed Cut
|1. Preparatory cut corresponds to 60 to 70 square feet of based area per acre; seed cut corresponds to 25 to 35 square feet of basal area per acre.|
By Glenn Hughes, Forestry Specialist
Mississippi State University does not discriminate on the basis of race, color, religion, national origin, sex, age, disability, or veteran status.
Extension Service of Mississippi State University, cooperating with U.S. Department of Agriculture. Published in furtherance of Acts of Congress, May 8 and June 30, 1914. Ronald A. Brown, Director