W. D. Boyer
Longleaf pine (Pinus palustris), whose species name means "of the marsh," has been locally referred to as longstraw, yellow, southern yellow, swamp, hard or heart, pitch, and Georgia pine. In presettlement times, this premier timber and naval stores tree grew in extensive pure stands throughout the Atlantic and Gulf Coastal Plains. At one time the longleaf pine forest may have occupied as much as 24 million ha (60 million acres), although by 1985 less than 1.6 million ha (4 million acres) remained.
Pinus palustris Mill.
Pine/scrub oak sandhills (PSOS-MT), mesic pine savannas (MPS-CP), wet pine flatwoods (WPF-T), wet pine savannas (SPS-T, SPS-RF, WLPS, VWLPS).
Abundant. Mar–Apr ; Sep–Oct . Thornhill 1066, 1067 (NCSC). Specimens seen in the vicinity: Sandy Run [ O’Berry ]: Taggart SARU 20 (WNC!). [= RAB, FNA, Weakley]
longstraw pine, southern yellow pine, Georgia pine
Pinus palustris P. Mill., longleaf pine, is found in the Atlantic and Gulf coastal plains from southeastern Virginia to central Florida and west to eastern Texas, and in the Piedmont region and Valley and Ridge province of Georgia and Alabama. Longleaf pine is a long-lived, native, evergreen conifer with scaly bark. Needles are in bundles of 3; they are shiny, dark green, and 8 to 15 inches long. Cones are 6 to 8 inches long. Mature trees attain a height of 100 to 120 feet and 2½ feet in diameter. Its seeds are the largest of all southern pines. It has extensive lateral roots and a taproot that grows 8 to 12 feet long.
Regularity: Regularly occurring
States or Provinces
AL FL GA HI LA MS NC SC TX VA
- The native range of longleaf pine.
Distribution and adaptation
Longleaf pine grows best in a warm, wet, temperate climate with an annual precipitation range of 43 to 69 inches. Although the species occurs in a wide variety of upland and flatwood sites, it is common on sandy, infertile, well-drained soils, mostly below 660 feet elevation.
Longleaf pine is distributed throughout the Southeast. For a current distribution map, please consult the Plant Profile page for this species on the PLANTS Website.
Habitat and Ecology
Key Plant Community Associations
Associated hardwoods on mesic coastal plain sites include southern red
oak (Quercus falcata), blackjack oak (Q. marilandica), water oak (Q.
nigra), flowering dogwood (Cornus florida), blackgum (Nyssa sylvatica),
sweetgum (Liquidambar styraciflua), persimmon (Diospyros virginiana) and
sassafras (Sassafras albidum). Associated hardwoods on xeric sandhill
sites include turkey oak (Q. laevis), bluejack oak (Q. incana), sand
post oak (Q. stellata var. margaretta), and live oak (Q. virginiana) .
Associated shrubs include gallberry (Ilex glabra), yaupon (I.
vomitoria), large gallberry (I. coriacea), wax-myrtle (Myrica
cerifera), shining sumac (Rhus copallina), blueberry (Vaccinium spp.),
huckleberry (Gaylussacia spp.), blackberry (Rubus spp.), saw palmetto
(Serena repens), sweetbay (Magnolia virginiana), swamp cyrilla (Cyrilla
racemiflora), and buckwheat-tree (Cliftonia monophylla) .
In longleaf pine's western range, groundcover includes bluestem
(Andropogon spp.) and panicum (Panicum spp.). In its eastern range,
pineland threeawn or wiregrass (Aristida stricta) is the primary
The published classifications listing longleaf pine as a dominant or
codominant species in community types (cts) are presented below:
Area Classification Authority
e TX, LA, MS general veg. cts Bridges & Orzell 1989
AL forest cts Golden 1979
SC veg. cts Nelson 1986
se US; Gulf Coast general forest cts Pessin 1933
se US general forest cts Waggoner 1975
NC veg. cts Wells 1928
Habitat: Rangeland Cover Types
This species is known to occur in association with the following Rangeland Cover Types (as classified by the Society for Range Management, SRM):
More info for the terms: cover, hardwood
SRM (RANGELAND) COVER TYPES :
808 Sand pine scrub
809 Mixed hardwood and pine
810 Longleaf pine-turkey oak hills
811 South Florida flatwoods
812 North Florida flatwoods
813 Cutthroat seeps
820 Everglades flatwoods
Habitat: Cover Types
This species is known to occur in association with the following cover types (as classified by the Society of American Foresters):
More info for the term: cover
SAF COVER TYPES :
69 Sand pine
70 Longleaf pine
71 Longleaf pine-scrub oak
75 Shortleaf pine
81 Loblolly pine
82 Loblolly pine-hardwood
83 Longleaf pine-slash pine
84 Slash pine
111 South Florida slash pine
Habitat: Plant Associations
This species is known to occur in association with the following plant community types (as classified by Küchler 1964):
KUCHLER  PLANT ASSOCIATIONS:
K112 Southern mixed forest
K115 Sand pine scrub
K116 Subtropical pine forest
This species is known to occur in the following ecosystem types (as named by the U.S. Forest Service in their Forest and Range Ecosystem [FRES] Type classification):
FRES12 Longleaf-slash pine
FRES13 Loblolly-shortleaf pine
Soils and Topography
Within the natural range of longleaf pine, three soil orders are of major importance. Ultisols are the dominant order and cover most of the southeastern United States outside of peninsular Florida. Ultisols most commonly associated with longleaf pine are the Typic Paleudults and Plinthic Paleudults. The other two soil orders are Entisols and Spodosols. Deep, sandy Entisols, primarily Quartzipsamments, range from about 3 m (10 ft) above sea level in Florida up to about 185 m (600 ft) in Georgia and the Carolinas. Entisols have not developed diagnostic horizons. They make up the Sandhills of the Carolinas, Georgia, and northwest Florida and the sand ridges in the central Highlands of peninsular Florida. Spodosols, particularly Aquods, are typical of the flatwoods of the lower Coastal Plain in Florida. They are wet, sandy soils with a fluctuating water table that is at or near the surface during rainy seasons (8).
Habitat & Distribution
Habitat & Distribution
Longleaf pine stands are successfully established by either seeding or vegetative reproduction. Seeds (including dormant seeds if prechilled) can be sown in the fall or spring, pressed into the soil at densities from 15 to 75 seedlings per square foot. Seeds germinate 1 to 2 weeks following seedfall. Germination requires mineral soil. The seed’s large size and persistent wing prevent it from penetrating through the litter. Seedlings are stemless after one growing season and this lasts from 2 to many years. During this grass-stage, the seedling develops an extensive root system, and the root collar increases in diameter. When the root collar diameter approaches 1 inch in diameter, height growth begins. A field-grown seedling grows 10 feet in 3 years once height growth is initiated. Branch production is delayed until the seedling reaches 10 to 16 feet in height.
Vegetative propagation is usually done by grafting. If grass-stage seedlings are top-killed, they can sprout from the root collar. Once height growth begins, sprouting ability decreases rapidly.
Heavy grazing can reduce tree density, significantly reducing establishment and causing crop failure.
Associated Forest Cover
Longleaf pine develops in close association with periodic surface fires. The vegetation associated with longleaf pine reflects the frequency and severity of burning. In the past, frequent fires resulted in open, parklike stands of longleaf with few other woody plants and a ground cover dominated by grasses. Ground cover in longleaf pine in the Coastal Plains can be separated into two general regions, with the division in the central part of south Alabama and northwest Florida. To the west, bluestem (Andropogon spp.) and panicum (Panicum spp.) grasses predominate; to the east, wiregrass (pineland threeawn, Aristida stricta) is most common.
With a reduction in fire occurrence, hardwoods and other pines encroach on the longleaf forest. Within the range of slash pine (Pinus elliottii), this species becomes increasingly important, leading to the cover type Longleaf Pine-Slash Pine. Elsewhere loblolly and shortleaf pines (P. taeda and P. echinata) as well as hardwoods gradually replace the longleaf, eventually resulting in Loblolly Pine-Hardwood (Type 82) or occasionally Loblolly Pine-Shortleaf Pine (Type 80). On poor, dry sandhills and mountain ridges, scrub hardwoods invade the understory creating forest cover type Longleaf Pine-Scrub Oak and finally Southern Scrub Oak (Type 72) as the pine disappears (12).
Hardwoods most closely associated with longleaf pine on mesic Coastal Plain sites include southern red, blackjack, and water oaks (Quercus falcata, Q. marilandica, and Q. nigra); flowering dogwood (Cornus florida); blackgum (Nyssa sylvatica); sweetgum (Liquidambar styraciflua); persimmon (Diospyros virginiana); and sassafras (Sassafras albidum). The more common shrubs include gallberry (Ilex glabra), yaupon (I. vomitoria), southern bayberry (Myrica cerifera), shining sumac (Rhus copallina), blueberry (Vaccinium spp.), huckleberry (Gaylussacia spp.), and blackberry (Rubus spp.). On xeric sandhill sites, the most common associates are turkey, bluejack, blackjack, sand post, and dwarf live oaks Quercus laevis, Q. incana, Q. marilandica, Q. stellata var. margaretta, and Q. minima). On the dry clay hills and mountains of Alabama, blackjack, post (Q. stellata) and southern red oaks, and mockernut hickory (Carya tomentosa) are found with longleaf pine. On low, wet flatwood sites near the coast, the most conspicuous understory plants are gallberry and saw-palmetto (Serenoa repens). Other common understory plants in low, wet Longleaf Pine or Longleaf Pine-Slash Pine types are sweetbay (Magnolia virginiana), swamp cyrilla (Cyrilla racemiflora), large gallberry (Ilex coriacea), buckwheat-tree (Cliftonia monophylla), blueberries, and blackberries.
Diseases and Parasites
Many species of birds, mice, and squirrels feed on longleaf pine seeds, the latter often taking them from unripe cones. Several species of ants feed on germinating seeds and cotyledon seedlings. Cottontails as well as other predators can destroy newly established seedlings. Grass-stage seedlings are vulnerable to destruction by hogs, pales weevil (Hylobius pales), and heavy livestock grazing. Pocket gophers cut seedlings off just below the ground surface.
Most seedling losses occur during the first year after establishment, untimely drought being the greatest single hazard. Logging of the overstory can destroy close to 50 percent of a seedling stand, although actual damage depends on type and season of logging, volume removed, and seedling size. Fire takes its toll of small, weak, or diseased seedlings.
Longleaf pine can be damaged by ice storms but is less susceptible to ice damage than slash pine (19).
The southern pine beetle (Dendroctonus frontalis) does not seem to afflict the species severely. The black turpentine beetle (Dendroctonus terebrans) can be a problem, especially on trees injured by turpentining, logging, or fire. Perhaps the greatest single cause of mortality in longleaf stands of pole and sawlog size is lightning, which is often followed by infestation by bark beetles (Ips spp.). Windthrow from hurricanes or tornados can cause heavy losses locally. Long term observations throughout the longleaf region have shown an average annual mortality of 1 tree per hectare (0.4/acre) in mature longleaf pine stands (4).
Fire Management Considerations
Prescribed burning in longleaf pine stands is used to control brown-spot needle blight, stimulate height growth, reduce excess fuel, control understory hardwoods, improve wildlife habitat, thin stands, and prepare a mineral seedbed [18,54].
Fire consumes foliage infected by brown-spot needle blight as well as inoculum in fallen leaves [29,54]. Burning is recommended when infection levels are greater than 20 percent and grass-stage root collars are larger than 0.3 inches (0.8 cm) in diameter or height-growth stage seedlings root collars are greater than 1.5 inches (3.8 cm). If the infection rate is higher than 20 percent, a high percentage of affected seedlings will die from the fire [18,35,45].
Annual spring fires are recommended to initiate height growth once grass-stage seedlings are large enough to withstand fire. In the spring, the green grass keeps the fire cool, and buds are protected by long sheaths of needles. However, grass-stage seedlings grown on poor sites may not tolerate light fire . Once height growth begins, the stand should not be burned for several years and then burned less frequently .
Late annual spring fires are recommended to gain control of hardwoods. Summer fires are also effective, but the risk of pine mortality is increased . Hardwoods are susceptible to fire in the late spring and summer because root reserves are low. Once hardwood populations are reduced, winter fire at 5-year intervals maintains longleaf pine stands, and enables a single fire in the spring or summer before seedfall to expose the necessary mineral soil seedbed [18,53].
Although longleaf pine regeneration is rarely excessive , a stand can be thinned by fire. In Alabama, a prescribed winter fire thinned a 1-year-old stand from 177,000 seedlings per acre (437,000/ha) to 6,300 per acre (15,600/ha) .Frequent late spring or early summer fires are necessary to recreate the longleaf pine-grassland savannahs that were common in presettlement times .
Broad-scale Impacts of Plant Response to Fire
The Fire Case Study Imperata cylindrica in a Florida sandhill
longleaf pine community provides information on fuel loads, prescribed
fire use, and postfire response of juvenile longleaf pines on cogon
grass (Imperata cylindrica)-infested sites and uninfested sites.
Plant Response to Fire
Fire can stimulate height-growth initiation of grass-stage seedlings. After three annual spring fires in Louisiana, most grass-stage seedlings had initiated height growth. It is thought that height growth is initiated because fire reduces competition and brown-spot needle blight infection. Late spring or summer fires are more effective at promoting height growth than winter fires [12,13,23]. However, annual fires begun only 1 year after germination stunt height growth .
Once a seedling has entered the height-growth stage, fire damage can decrease growth. Annual fires have reduced basal area growth of young longleaf pine by 22 to 44 percent . In Alabama, prescribed biennial fires begun in 14-year-old stands averaging 22 feet (6.7 m) in height and 3.2 inches (8.1 cm) in diameter reduced growth, even though no crown scorch was observed. The impact on growth of biennial fires worsened with time. The season of fire had no effect .
Older longleaf pine shows no growth loss if there is little or no needle scorch . Seed production of mature trees is not affected by frequent fire.
Seed will germinate on mineral soil exposed by fire .
Trees in regularly burned stands develop a buttressed trunk which results in stump taper .
Immediate Effect of Fire
Open-grown grass-stage seedlings with root collar diameters smaller than 0.3 inch (0.8 cm) can be killed by light fire [7,29]. Under a pine overstory, light fire can kill seedlings smaller than 0.5 inch (1.3 cm) in diameter, because excess pine litter under the canopy makes the fire hotter [3,18,44]. In a prescribed winter fire in Alabama, 1-year-old seedlings with exposed root collars were more susceptible to fire than seedlings with root collars at or near the soil surface . Larger grass-stage seedlings are highly resistant to fire.
In the height-growth stage, seedlings 1 to 3 feet (0.3-0.9 m) tall are extremely vulnerable to fire [20,29]. If the terminal bud is destroyed, the seedling will die . Once a seedling is about 3.3 feet (1 m) tall, it is likely to survive low-severity ground fires . After the sapling is 10 feet (3 m) tall, it is very fire tolerant . Trees 10 inches (25 cm) in diameter and larger survive all but the most severe fires . A high-severity crown fire kills some mature trees and nearly all trees smaller than 10 inches (25 cm) in diameter .
Longleaf pine needles were killed instantly when immersed in water at 147 degrees Fahrenheit (64 deg C) but survived 11 minutes at 126 degrees Fahrenheit (52 deg C) .
Longleaf pine is classified as fire-resistant [10,36]. It is ideally suited to a high-frequency, low-severity surface fire regime. The natural fire interval is every year to every 5 to 10 years . Most natural fires are caused by lightning and occur in late spring and summer [37,44].
Longleaf pine has many adaptations to fire. The grass-stage seedling is resistant to fire. If top-killed, it sprouts from the root collar. Once the terminal bud develops, it is protected by a moist, dense tuft of needles. As the tuft burns towards the bud from the needle tips, water is vaporized. The steam reflects heat away from the bud and extinguishes the fire [37,38]. The bud also has scales for protection and a silvery pubescence that probably reflects heat [29,37].
During the grass-stage, the seedling invests heavily in a taproot and in root collar size. When height growth is initiated, often the year after a fire, the seedling uses its stored reserves to quickly grow a straight stem with no branches. After one growing season, the terminal bud is usually above the level of the next surface fire [37,38].
In addition to fire resistant adaptations, longleaf pine has a pyrogenic strategy. Spring and summer fires are beneficial because they reduce competition and expose the mineral soil necessary for seed germination in the fall. Long, resin-filled needles have short persistence and form a highly flammable, well-aerated litter. Resin is also concentrated in the bole and roots of older trees and snags. These trees act as lightning receptors. A smoldering tree can ignite the ground several days or weeks later when the ground litter has dried out. Longleaf pine communities often have a grass understory that readily ignites. [28,37,43]. Because of open stands and high and open crowns, crown fires are rare .
More info for the term: competition
Longleaf pine is intolerant of shade and competition. With frequent fire, uneven-aged pure stands of longleaf pine form parklike savannahs [7,20,37]. Because longleaf pine regenerates in openings created by the death of mature trees, small clusters of trees of the same age are dispersed throughout the stand . In the absence of frequent fire, longleaf pine is replaced by hardwoods and other southern pines [7,54]. Loblolly pine and shortleaf pine will invade and soon dominate a site of grass-stage longleaf pine . Recruitment of longleaf pine ceases 15 years after fire. Invasion by hardwoods accelerates the decline of mature longleaf pine .
Longleaf pine is classified as a fire subclimax [18,19,20,45]. Lightning, which historically ignited the frequent fires, is a component of a long-term climatic pattern. As long as there is lightning, longleaf pine can perpetuate itself indefinitely on a site.
Seed production and dissemination: Longleaf pine is monoecious. It begins producing cones when it reaches about 30 years of age or 10 inches (25 cm) in diameter [18,38]. The best cone producers are 15-inch-diameter (38 cm) open-grown trees. Cones contain, on average, 35 seeds . Longleaf pine masts every 7 to 10 years, but healthy trees will produce a fair to good seed crop every 3 to 4 years [2,37,38]. The winged seeds are dispersed a short distance by wind with 71 percent of the seeds falling within 66 feet (20 m) of the base of the parent tree .
Germination and seedling development: Seeds germinate 1 to 2 weeks after seedfall. Germination is epigeal and requires mineral soil. The seed's large size and persistent wing prevent it from penetrating through the litter. Seedlings are stemless after one growing season and this "grass-stage" lasts from 2 to many years [7,18,38]. It may last as long as 20 years if brown-spot needle blight or competition is severe [18,45]. During the grass-stage, the seedling develops an extensive root system, and the root collar increases in diameter. When the root collar diameter approaches 1 inch (2.5 cm) in diameter, height growth begins. An open-grown seedling grows 10 feet (3 m) in 3 years once height growth is initiated [7,37,54]. Branch production is delayed until the seedling reaches 10 to 16 feet (3-5 m) in height .
Vegetative reproduction: If grass-stage seedlings are top-killed, they can sprout from the root collar. Once height growth begins, sprouting ability decreases rapidly .
Growth Form (according to Raunkiær Life-form classification)
Crown-stored residual colonizer; short-viability seed in on-site cones
Off-site colonizer; seed carried by wind; postfire years one and two
Reaction to Competition
Life History and Behavior
Longleaf pine seed develops in a 3-year process. Strobili are initiated during midsummer. Conelets emerge in late winter. Catkins emerge in November, then remain dormant until late winter. Pollination occurs from late February in the South to early April in the North. Fertilization does not occur until the following spring. Cones reach maturity in mid-September to mid-October after their second season of growth. Seed is dispersed from late October to November and the majority of seed falls in 2 to 3 weeks. Seed germinates 1 to 2 weeks later. Primary needles appear soon after germination and secondary needles about 2 months later [7,18].
Seeds require contact with mineral soil for satisfactory germination and establishment. Longleaf seeds, with their large wings, cannot easily reach mineral soil through a heavy cover of grass and litter. The accumulated material must be removed before seedfall, either mechanically or by burning. Burning within a year of seedfall normally provides an adequate seedbed. Lack of seedbed preparation can result in a regeneration failure.
Germination of longleaf pine seed is epigeal (26). Newly germinated seedlings have virtually no above-ground hypocotyl, and the cotyledons are close to the ground line. The primary needles appear after germination and the secondary needles about 2 months later. The epicotyl, or stem above the cotyledons, does not elongate rapidly as in most other pines. Even in the nursery, seedlings are virtually stemless after one growing season (16). This stemless condition is one of the unique characteristics of longleaf pine. It is referred to as a grass stage and may last 2 to many years, depending on growth conditions. During this time, longleaf is most susceptible to its major disease, the brown-spot needle blight, Scirrhia acicola (11).
While in the grass stage, seedlings develop extensive root systems. Growth can be followed by observing the increase in root-collar diameter. When it approaches 2.5 cm (1 in), active height growth is imminent. Grass-stage seedlings, once they reach 0.8 cm (0.3 in) in root-collar diameter, are highly resistant to fire, even during the growing season. Seedlings in early height growth, up to a height of about 0.6 to 0.9 m (2 to 3 ft), become susceptible to damage by fire. Once beyond this stage, longleaf pines are again fire resistant.
Competition and brown-spot needle blight have great impact on the rate of seedling development and together largely determine the duration of the grass stage. Longleaf seedlings can be easily established and usually survive for years under an overstory of parent pines. Growth, however, is very slow. Seedlings respond promptly with an increased rate of growth when released from overstory competition.
Growth rate varies widely among individuals in a natural seedling stand, and vigorous fast-growing seedlings express dominance early. The rapid breakup of a seedling stand into a wide range of size classes reduces the risk of stand stagnation. About 10 percent of a natural seedling stand shows resistance to the brown-spot disease, and this gives them a growth advantage that persists for many years. At age 24, trees that had little or no brown-spot infection averaged 2.4 in (8 ft) taller than trees that had 30 percent or more of their foliage destroyed by the disease as seedlings (1).
A low level of competition permits early initiation of height growth. One longleaf pine plantation on a prepared site had nearly 60 percent of the trees in active height growth by the end of the second growing season, and over 90 percent by the end of the third. Early initiation of height growth circumvented a brown-spot problem as the disease did not have time to build up to serious proportions.
Seed Production and Dissemination
Seed production per hectare reaches a peak at stand densities between 6.9 and 9.2 m²/ha (30 to 40 ft²/acre) of basal area, assuming that the stand is comprised of dominant-codominant trees of cone bearing size (3). A shelterwood stand with a basal area of 6.9 m²/ha (30 ft²/acre) produces three times as many cones per unit area as a stand of scattered seed trees averaging 2.3 m²/ha (10 ft²/acre) in good seed years (11).
Throughout its range, longleaf pine in shelterwood stands produces seed crops adequate for natural regeneration, about 2,500 cones per hectare (1,000/acre), on the average of once every 4 to 5 years (11). However, everything else being equal, good cone crops are more frequent in some parts of the longleaf pine range than in others, so the general average may be meaningless at a given location. The production of female strobili is much less variable from place-to-place than is the production of mature cones, indicating that geographic differences in cone production are due more to conelet and cone losses than failure to produce conelets in the first place (7).
When a shelterwood stand is created by cutting back a stand of substantially higher density, increased cone production resulting from release does not occur until the end of the third growing season after cutting (9). Release that occurs after conelet initiation has no effect on that crop, other than promoting better conelet survival through reduced stress in dry periods.
Seeds are dispersed by the wind. Seed dispersal begins in late October and continues through November, with the majority falling within a period of 2 to 3 weeks. The time and duration of seed dispersal vary depending on weather conditions. Dispersal range is limited, with 71 percent of sound seeds falling within a distance of 20 m (66 ft) of the base of parent trees (11).
Longleaf seeds are the largest of the southern pines. The number of cleaned seeds ranges from 6,600 to 15,400/kg (3,000 to 7,000/lb), averaging 10,800/kg (4,900/lb) (26).
Flowering and Fruiting
Since rainfall patterns associated with catkin initiation differ from those favoring conelets, large crops of male and female flowers do not necessarily coincide. Ten years of observation did not show any correlation between size of conelet and pollen crops in longleaf pine.
Variable but usually heavy annual losses of longleaf pine conelets can be expected; observed losses have ranged from 65 to 100 percent (2,24,30). Several agents, alone or in combination, may be responsible. The more important appear to be insects, bad weather, and insufficient pollen. Over 15 years at one location, cone production was related to pollen density, to the point of a sufficiency of pollen (2). Further increases in pollen density had little effect. In some cases, nearly all the losses have been attributed to insects (24), while in others the more common causes of conelet losses were not responsible (30). Most conelet losses seem to occur in the spring, at about the time of pollination, although substantial losses may also occur in the summer (24). Most of the spontaneous conelet abortions in longleaf pine may result from excess ethylene production by foliage and shoots. A foliar spray with anti-ethylene compounds soon after anthesis has reduced conelet abortion by half, doubling seed yields (18).
Catkin buds normally emerge in November, then remain dormant for about a month before growth resumes. Conelet buds emerge in January or February. The rate of development of both conelets and catkins thereafter is almost entirely dependent on ambient temperature. Catkins are purple from the time they emerge from the buds until they shed their pollen. Upon emerging from the bud, conelets are red until they are pollinated, after which they gradually fade to a yellowish green. Most mature catkins range from 3 to 5 cm (1.2 to 2.0 in) in length.
The average date of peak pollen shed and conelet receptivity may range from late February in the southern part of longleaf pines' range to early April toward the northern limits. Most locations may experience flowering dates close to these extremes. The date of peak pollen shed and conelet receptivity coincides on individual longleaf pine trees but can vary considerably among trees in a stand. Some trees are consistently early and others late in time of flowering, although the differences vary from year to year, depending on air temperatures before and during the flowering period (5). Over 22 years of observation, the time required for shedding 80 percent of all pollen in a longleaf pine stand ranged from 5 to 21 days and averaged 13 (5).
Pollination takes place in the late winter or spring, but fertilization does not occur until the following spring. At this time conelets are growing rapidly, increasing in length from about 2.5 cm (1 in) in February to about 18 cm (7 in) by May or June (16). Mature cones range in length from 10 to 25 cm (4 to 10 in). Cones reach maturity between mid-September and mid-October of their second year. Cones, as they become ripe, change color from green to dull brown, although cones may be ripe before the color change (26). The specific gravity of ripe cones ranges from 0.80 to 0.89. Ripeness can be tested by flotation in SAE 20 motor oil; ripe cones will float but those not yet ripe will sink (26).
Growth and Yield
The critical element in the growth of longleaf pine stands is the duration of the grass stage. About 70 percent of the variation among plantations in the form of height-over-age curves was related to the condition of the planting site: early height growth on unprepared cutover sites was much slower than on old fields and mechanically prepared cutover sites (6).
Reduction of competing ground cover in grass stage seedling stands can have a large impact on growth and future volume yields. One study (25) observed the effects of a single aerial application of 2,4,5-T to stands of 1-year-old longleaf seedlings. Twenty years later, treated stands had significantly greater tree diameter (10 percent), height (17 percent), and total volume per unit area (32 percent) than adjacent untreated stands, although there was no difference in the number of trees per unit area. Treated stands averaged 83.5 m³/ha (1,193 ft³/acre) total inside-bark (i.b.) volume, compared to 63.2 m³/ha (904 ft³/acre) for untreated stands.
Longleaf pine growth and yield predictions have been published for periodically thinned even-aged natural stands (15) and also for unthinned plantations in the west Gulf region (22). Predicted total volume (i.b.) yields for two common site index classes are given in table 1. The merchantable proportion of total volume ranges from 78 to 86 percent at age 20, to 97 to 98 percent at age 40. The peak in periodic annual increment is reached between ages 20 and 30.
Table 1- Predicted total volume yields inside bark for even-aged natural stands of longleaf pine Site index at base age 50 years Stand in age in years¹
21.3 m or 70 ft
24.4 m or 80 ft m²/ha m³/ha m³/ha 20 13.8 61 71 25 20.0 110 128 30 25.5 160 187 35 29.6 207 241 40 33.1 248 289 ft²/acre ft³/acre ft³/acre 20 60 874 1,019 25 87 1,572 1,832 30 111 2,287 2,666 35 129 2,954 3,443 40 144 3,549 4,137 ¹Determined from ring counts taken at 1.2 m (4 ft), plus 7 years. The optimum stand density to maintain by periodic thinning varies by site and management goals. A rather broad range of stand densities, above a basal area of about 13.8 m²/ha (60 ft²/acre), produces near maximum periodic volume growth (13). Lower densities concentrate growth on fewer trees. Longleaf responds well to release provided by thinning if the released trees have crowns equal to at least one-third to one-half of total tree height. Small-crowned intermediate or suppressed trees do not respond promptly to release. Thinning should be from below to release well-formed dominant and codominant trees.
Present indications are that longleaf pine plantations should produce volume growth similar to natural stands if other factors are equal. To the extent that plantations have had better competition control, with consequent acceleration of early growth, a particular volume yield should be reached at an earlier age in plantations than in natural stands.
Evolution and Systematics
Roots of longleaf pine protect from strong winds by forming both large anchoring taproots and a widespread lateral root system.
"The damage resistance of longleaf pine could be related to firm anchorage provided by the large taproot and widespread lateral root system. Our excavations of longleaf pine root systems (Baruch Forest Science Institute, pers. comm.) indicated that longleaf pine taproots extended two meters vertically in the soil and the lateral root system extended up to six meters horizontally from the taproot." (Gresham et al. 1991:425)
"While no systematic study has yet been done, at least four distinct schemes seem to be used to keep roots and soil in decent contiguity. Combinations of more than a single scheme certainly occur, and a given tree may use different schemes or a varying mix of several as it grows from a sapling. (Mattheck  considers some aspects of the tree's problem; Ennos and Fitter  provide information on anchorage in small plants or very young trees; Ennos  gives a good general view of the situation.)...
"An alternative scheme capitalizes on little more than the ability of soil to withstand compressive force. If the trunk is continued downward beneath the soil as a stiff taproot, and if ramifying lateral roots near the soil's surface fix the location of the tree, then pushing the trunk in one direction will push the taproot in the other (Edelin and Atger 1994). Soil, especially when beneath a layer of superficial roots, ought to resist this sideways push quite well; the scheme, which we might just call 'taprooting' is shown in figure 21.3c. Taprooting depends on good resistance of the taproot to bending as a cantilever--a high level of flexural stiffness--as is sufficient broadside area to push against so as not to slip sideways through soil. (Additional substantial vertical 'striker' roots, according to Perry  and Crook and Ennos , may supplement the mechanical role of taproots.)
"A tree that uses the scheme without a healthy taproot is crippled. In over 25 years only one of over seventy loblolly pines (Pinus taeda) around my house has blown over with less than really severe provocation; that one had a rotted taproot. (Taproots normally break when a tree uproots, so they're easily overlooked.) My casual observations of several excavated pines suggest that taproots may develop noncylindrical cross sections in response to wind from a prevailing direction. But when poking around the bases of large uprooted Douglas firs, I was struck by the small size of the taproot breakage points. Of the schemes here, the relative importance of taprooting is the least certain; the best documentation of its role comes from work on larch, by Crook and Ennos (1996)." (Vogel 2003:431,433)
Learn more about this functional adaptation.
- Gresham, C. A.; Williams, T. M.; Lipscomb, D. J. 1991. Hurricane Hugo Wind Damage to Southeastern US Coastal Forest Tree Species. Biotropica. 23(4): 420-426.
- Steven Vogel. 2003. Comparative Biomechanics: Life's Physical World. Princeton: Princeton University Press. 580 p.
Molecular Biology and Genetics
Variation among individual trees is greater than that among stands or among geographically diverse seed sources (23,28). Nevertheless, the diversity of environments throughout the longleaf range has promoted the development of genetic variation among populations. According to rangewide provenance tests, trees from coastal areas usually outgrow those from inland areas at all but the coldest locations. Trees originating from the central Gulf Coast should be more productive than trees from other sources on most coastal plain longleaf sites from Georgia and north Florida west to east central Louisiana (28). Elsewhere, local seed sources may be safest to use until more information is available.
Hybrids The major southern pines, as well as some minor species, are closely related and have overlapping ranges. Natural hybridization has contributed to genetic diversity among trees and populations. Natural hybridization is common between longleaf and loblolly pine, producing the Sonderegger pine (P. x sondereggeri H. H. Chapm.). This is the only named southern pine hybrid. Throughout much of the longleaf pine range, the flowering of longleaf and loblolly pines overlaps in most years so there is no phenological barrier to natural crossing. Natural hybridization between longleaf and slash pine is unlikely, based on differences between the species in dormancy and heat requirements for flowering (5).
Artificial crosses between longleaf pine and both loblolly and slash pines can be achieved easily. Crosses between longleaf and shortleaf pine have not been found in nature but have been produced artificially. There are no reported successful crosses of longleaf pine with any other pine species (28).
Barcode data: Pinus palustris
Statistics of barcoding coverage: Pinus palustris
Public Records: 5
Specimens with Barcodes: 13
Species With Barcodes: 1
IUCN Red List Assessment
Red List Category
Red List Criteria
National NatureServe Conservation Status
Rounded National Status Rank: N5 - Secure
NatureServe Conservation Status
Rounded Global Status Rank: G5 - Secure
Only a few old-growth stands of longleaf pine remain in the southeastern United States . Although longleaf pine is not an endangered species, many endangered plant and animal species live in longleaf pine communities. Longleaf pine communities are ranked as threatened by the Texas Natural Heritage Program .
Please consult the PLANTS Web site and your State Department of Natural Resources for this plant’s current status (e.g. threatened or endangered species, state noxious status, and wetland indicator values).
Pests and potential problems
The main disease of longleaf pine is brown-spot needle blight (Scirrhia acicola). Other diseases include pitch canker, annosus root rot, and cone rust. Insects that attack longleaf pine include black turpentine beetle, bark beetles, and seed bugs.
Longleaf pine communities are estimated to have once covered 59 to 87
million acres (24-35 million ha); now only 5 to 10 million acres (2-4
million ha) remain. Of that remaining, most is second growth and
in poor condition [40,41]. Because of its timber value and because longleaf
pine communities house many endangered plant and animal species, forest
managers are attempting to regenerate more longleaf pine communities.
Natural regeneration of longleaf pine is difficult because of poor seed
production, heavy seed predation by animals, poor seedling survival, and
slow seedling growth. Longleaf pine is best managed with even-aged
silviculture using a three-cut shelterwood system [2,5,18,25]. The
preparatory cut, 10 years before expected seed crop, should leave a
basal area of 60 to 70 square feet per acre (13.8-16.1 sq m/ha). The
remaining trees will develop larger crowns and increase seed production.
The seed cut, 5 years before the expected seed crop, should leave a
basal area of 30 square feet per acre (6.9 sq m/ha). The seedbed should
be prepared, usually with fire, when a good seed crop is evident from
large numbers of conelets. Seed trees should be removed 1 to 2 years
after seedlings are established and before height growth has been
The group selection method can be used to naturally regenerate
uneven-aged stands. Up to 2 acres (0.8 ha) of trees should be cut so
discernible openings are created .
Methods for artificial regeneration of longleaf pine are detailed in
Rounsaville 1989 .
Disease and insects: Longleaf pine is highly resistant to most diseases
and insects that infect other southern pines. The main disease of
longleaf pine is brown-spot needle blight (Scirrhia acicola).
Defoliation suppresses and eventually kills grass-stage seedlings .
Infection of seedlings is less severe under a pine overstory than in the
open . About 20 percent of seedlings are resistant to brown-spot
needle blight . (See Fire Management).
Other diseases include pitch canker (Fusarium moniliforme var.
subglutinans), annosus root rot (Heterobasidion annosum), and cone rust
(Cronartium strobilinum). Insects that attack longleaf pine include
black turpentine beetle (Dendroctonus terebrans), bark beetles (Ips
spp.), and seed bugs (Tetyra bipunctata and Leptoglossus corculus),
which can decimate a seed crop .
Predation: Despite fall germination, which minimizes the time seed lies
on the forest floor, predation by birds and small mammals can decimate a
seed crop .
Weather: Because of the fall germination, low winter temperatures can
damage cotyledons. March frosts can destroy flowers. Hurricanes,
tornadoes, and lightning cause local damage [7,18].
Other considerations: Moderate cattle grazing has no effect on longleaf
survival, but heavy grazing reduces young tree density by 20 percent
. Hogs significantly reduce longleaf pine establishment and can
cause crop failure .
Cultivars, improved and selected materials (and area of origin)
No cultivars are currently recommended. Seeds and seedlings are commercially available from woody plant seed companies. The number of seeds per pound ranges from 3,000 to 7,000.
Longleaf pine is intolerant to both shade and competition. With frequent fire, uneven-aged pure stands form park-like savannahs. Because longleaf pine regenerates in openings created by dead trees, small clusters of trees of the same age are dispersed throughout the stand. In the absence of frequent fire, the species is replaced by hardwoods and other southern pines; this hastens the decline of mature longleaf pine. Lightning ignited fires are pivotal to perpetuation of longleaf pine on a site indefinitely. Excessive grazing reduces young tree density.
Relevance to Humans and Ecosystems
Other uses and values
Longleaf pine's needles are used for mulch. Resin is used in the naval stores industry for gum turpentine and rosin production .
Wood Products: Longleaf pine, a valued timber species, has clear, straight wood with few defects . It was used extensively in the past for timber and ship building. Most virgin stands have now been harvested. Because longleaf pine is not as easy to regenerate as other southern pine timber species, it is not used as extensively as it once was. Longleaf pine's highly desirable wood, however, has stimulated efforts to regenerate it [7,18].
Importance to Livestock and Wildlife
Longleaf pine forests provide excellent habitat for bobwhite quail, white-tailed deer, wild turkey, and fox squirrel. Sixty-eight species of birds utilize longleaf pine forests . Birds, and mice, squirrels, and other small mammals eat the large seeds. Ants eat germinating seeds, and razorback hogs eat the roots of seedlings [7,54]. Old-growth longleaf pine stands provide nesting habitat for the endangered red-cockaded woodpecker .
Nutritional value: Longleaf pine seed is more than 25 percent protein and more than 0.05 percent phosphorus .
Value for rehabilitation of disturbed sites
Erosion Control: Longleaf pine is a highly recommended species for reforestation of dry, infertile, deep sands in the southeastern U.S. It is has limited potential for rehabilitation of mine spoils.
Wildlife: Birds and small mammals eat the large seeds, ants feed on germinating seeds, and razorback hogs eat the roots of seedlings. This species provides excellent habitat for bobwhite quail, white-tailed deer, wild turkey, and fox squirrel. Old-growth stands provide nesting habitat for the red-cockaded woodpecker.
Timber: The wood is often clear, straight, and with few defects and used for timber and ship building.
Recreation and Beautification: Longleaf pine needles are used for mulch. Resin is used in the naval stores industry for gum turpentine and rosin production.
Pinus palustris, commonly known as the longleaf pine, is a pine native to the southeastern United States, found along the coastal plain from eastern Texas to southeast Virginia, extending into northern and central Florida. The Longleaf Pine Is Historically native to Maryland and Delaware
It reaches a height of 30–35 m (98–115 ft) and a diameter of 0.7 m (28 in). In the past, they reportedly grew to 47 m (154 ft) with a diameter of 1.2 m (47 in).
The bark is thick, reddish-brown, and scaly. The leaves are dark green and needle-like, and occur in bundles of three. They often are twisted and 20–45 cm (7.9–17.7 in) in length. It is one of the two southeastern U.S. pines with long needles, the other being slash pine.
The cones, both female seed cones (ovulate strobili) and male pollen cones (staminate strobili), are initiated during the growing season before buds emerge. Pollen cones begin forming in their buds in July, while seed conelets are formed during a relatively short period of time in August. Pollination occurs early the following spring, with the male cones 3–8 cm (1.2–3.1 in) long. The female (seed) cones mature in about twenty months from pollination; when mature they are yellow-brown in color, 15–25 cm (5.9–9.8 in) long, and 5–7 cm (2.0–2.8 in) broad, opening to 12 cm (4.7 in), and have a small, but sharp, downward-pointing spine on the middle of each scale. The seeds are 7–9 mm (0.28–0.35 in) long, with a 25–40 mm (0.98–1.57 in) wing.
Longleaf pine takes 100 to 150 years to become full size and may live to 500 years old. When young, they grow a long taproot, which usually is 2–3 m (6.6–9.8 ft) long; by maturity they have a wide spreading lateral root system with several deep 'sinker' roots. It grows on well-drained, usually sandy soil, often in pure stands. In northern Alabama, it sometimes occurs on clay soil. The scientific name meaning, "of marshes," is a misunderstanding on the part of Philip Miller who described the species, after seeing longleaf pine forests with temporary winter flooding.
Longleaf pine also is known as being one of several species grouped as a southern yellow pine or longleaf yellow pine, and in the past as pitch pine (a name dropped as it caused confusion with pitch pine, Pinus rigida).
Longleaf pine is highly pyrophytic (resistant to wildfire). Periodic natural wildfire selects for this species by killing other trees, leading to open longleaf pine forests or savannas. New seedlings do not appear at all tree-like and resemble a dark green fountain of needles. This form is called the grass stage. During this stage, which lasts for 5–12 years, vertical growth is very slow, and the tree may take a number of years simply to grow ankle-high. After that it makes a growth spurt, especially if there is no tree canopy above it. In the grass stage, it is very resistant to grass fires, which burn off the ends of the needles, but the fire cannot penetrate the tightly-packed needle bases to reach the bud. While relatively immune to fire, at this stage, the plant is quite appealing to feral pigs, and the early settlers' habit of releasing swine into the woodlands to feed was greatly responsible for the decline of the species.
Longleaf pine forests are rich in biodiversity. They are well-documented for their high levels of plant diversity, in groups including sedges, grasses, carnivorous plants and orchids. These forests also provide habitat for gopher tortoises, which, as keystone species, dig burrows that provide habitat for hundreds of other species of animals. The red-cockaded woodpecker is dependent on mature pine forests and is now endangered as a result of this decline. Longleaf pine seeds are large and nutritious, forming a significant food source for birds (notably the brown-headed nuthatch) and other wildlife. There are 9 salamander species and 26 frog species that are characteristic of pine savannas, along with 56 species of reptiles, 13 of which could be considered specialists on this habitat.
The Red Hills Region of Florida and Georgia is home to some of the best preserved stands of longleaf pine. These forests have been burned regularly for many decades to encourage bobwhite quail habitat in private hunting plantations.
Vast forests of longleaf pine once were present along the southeastern Atlantic coast and Gulf Coast of North America, as part of the eastern savannas. These forests were the source of naval stores - resin, turpentine, and timber - needed by merchants and the navy for their ships. They have been cutover since for timber and usually replaced with faster-growing loblolly pine and slash pine, for agriculture, and for urban and suburban development. Due to this deforestation and over-harvesting, only about 3% of the original longleaf pine forest remains, and little new is planted. Longleaf pine is available, however, at many nurseries within its range; the southernmost known point of sale is in Lake Worth, Florida.
The yellow, resinous wood is used for lumber and pulp. Boards cut years ago from virgin timber were very wide, up to 1 m (3.3 ft), and a thriving salvage business obtains these boards from demolition projects to be reused as flooring in upscale homes.
The extremely long needles are popular for use in the ancient craft of coiled basket making.
The stumps and taproots of old trees become saturated with resin and will not rot. Farmers sometimes find old buried stumps in fields, even in some that were cleared a century ago, and these usually are dug up and sold as Fatwood, "fat lighter" or "lighter wood" which is in demand as kindling for fireplaces, wood stoves, and barbecue pits. In old growth pine the heartwood of the bole is often saturated in the same way. When boards are cut from the fat lighter wood, they are very heavy and will not rot, but buildings constructed of them are quite flammable and make extremely hot fires.
Native Range, Restoration, and Protection
Before European settlement, longleaf pine forest dominated as much as 90,000,000 acres (360,000 km2) stretching from Virginia south to Florida and west to eastern Texas. Its range was defined by the frequent widespread fires that occurred throughout the southeast. In the late 19th century, these virgin timber stands were "among the most sought after timber trees in the country." This rich ecosystem now has been relegated to less than 5% of its pre-settlement range due to clear cutting practices:
As they stripped the woods of their trees, loggers left mounds of flammable debris that frequently fueled catastrophic fires, destroying both the remaining trees and seedlings. The exposed earth left behind by clear cutting operations was highly susceptible to erosion, and nutrients were washed from the already porous soils. This further destroyed the natural seeding process. At the peak of the timber cutting in the 1890s and the first decade of the new century, the longleaf pine forests of the Sandhills were providing millions of board feet of timber each year. The timber cutters gradually moved across the South; by the 1920s, most of the "limitless" virgin longleaf pine forests were gone.
In "pine barrens" most of the day. Low, level, sandy tracts; the pines wide apart; the sunny spaces between full of beautiful abounding grasses, liatris, long, wand-like solidago, saw palmettos, etc., covering the ground in garden style. Here I sauntered in delightful freedom, meeting none of the cat-clawed vines, or shrubs, of the alluvial bottoms. -John Muir
Efforts are being made to restore longleaf pine ecosystems within its natural range. Some groups such as the Longleaf Alliance are actively promoting research, education, and management of the longleaf pine.
The USDA offers cost-sharing and technical assistance to private landowners for longleaf restoration through the NRCS Longleaf Pine Initiative. Similar programs are available through most state forestry agencies in the longleaf's native range. In August 2009, the Alabama Forestry Commission received 1.757 million dollars in stimulus money to restore longleaf pines in state forests.
There are four large core areas within the range of the species that provide the opportunity to protect the biological diversity of the coastal plain, as well as to restore wilderness areas east of the Mississippi River. Each of these four (Eglin Air Force Base: 187,000+ ha; Apalachicola National Forest: 228,000+ ha; Okefenokee-Osceola: 289,000+ ha; De Soto National Forest: 200,000+ ha) have nearby lands that offer the potential to expand the total protected territory for each area to well beyond 500,000 ha. These areas would provide the opportunity not only to restore forest stands, but to restore populations of native vertebrate animals threatened by landscape fragmentation.
Notable eccentric populations exist within the Uwharrie National Forest in the central Piedmont region of North Carolina. These have survived owing to relative inaccessibility and, in one instance, intentional protection in the 20th century by a private landowner (a property now owned and conserved by the Land Trust of Central North Carolina).
The United States Forest Service is conducting prescribed burning programs in the 258,864-acre Francis Marion National Forest, located outside of Charleston, South Carolina. They are hoping to increase the longleaf pine forest type to 44,700 acres (181 km2) by 2017 and 53,500 acres (217 km2) in the long term. In addition to Longleaf restoration, prescribed burning will enhance the endangered Red-cockaded Woodpeckers' preferred habitat of open, park-like stands, provide habitat for wildlife dependent on grass-shrub habitat, which is very limited, and reduce the risk of damaging wildfires.
Since the 1960s, Longleaf restoration has been ongoing on almost 95,000 acres of state and federal land in the sandhills region of South Carolina, between the piedmont and coastal plain. The region is characterized by deep, infertile sands deposited by a prehistoric sea, with generally arid conditions. By the 1930s, most of the native longleaf had been logged, and the land was heavily eroded. Between 1935-1939, the federal government purchased large portions of this area from local landowners as a relief measure under the Resettlement Administration. These landowners were resettled on more fertile land elsewhere. Today, the South Carolina Sand Hills State Forest comprises approximately half of the acreage, and half is owned by the United States Fish and Wildlife Service as the adjacent Carolina Sandhills National Wildlife Refuge. At first, restoration of forest cover was the goal. Fire suppression was practiced until the 1960s, when prescribed fire was introduced on both the state forest and the Sandhills NWR  as part of the restoration of the longleaf/wiregrass ecosystem.
A 2009 study by the National Wildlife Federation says that longleaf pine forests will be particularly well adapted to environmental changes caused by global warming. 
- Longleaf Pine Ecosystem
- Sonderegger Pine, a hybrid between loblolly and longleaf species
- Mountain Longleaf National Wildlife Refuge
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- Means, D. Bruce. 2006. Vertebrate faunal diversity in longleaf pine savannas. Pages 155-213 in S. Jose, E. Jokela and D. Miller (eds.) Longleaf Pine Ecosystems: Ecology, Management and Restoration. Springer, New York. xii + 438 pp.
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|Wikimedia Commons has media related to Pinus palustris.|
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- "Longleaf pine/wiregrass ecosystem". Carolina Sandhills National Wildlife Refuge. Retrieved 2009-04-04.
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Longleaf pine ( Pinus palustris ) is the state tree of North Carolina.
Names and Taxonomy
The currently accepted scientific name of longleaf pine is Pinus
palustris Mill. [7,31]. There are no recognized varieties or subspecies.
Longleaf pine forms natural hybrids with loblolly pine (P. taeda) and
slash pine (P. elliottii), although the latter are rare [7,26].
southern yellow pine
longleaf yellow pine
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