Pinus palustris Mill.
Range and Habitat
The native range of longleaf pine. (From Little, 1971.)
Geographic Range
According to Boyer (1990) :
"The natural range of longleaf pine includes most of the Atlantic and Gulf
Coastal Plains from southeastern Virginia to eastern Texas and south through
the northern two-thirds of peninsular Florida. The species also grows in the
Piedmont, Ridge and Valley, and Mountain Provinces of Alabama and northwest
Georgia."
Climate
According to Boyer (1990) :
"Longleaf pine grows in warm, wet temperate climates characterized by hot
summers and mild winters. Annual mean temperatures range from 16° to 23° C (60° to 74° F) and annual precipitation from 1090 to 1750 mm
(43-50 in) in the Carolinas and Texas and the greatest along the Gulf Coast
of Alabama, Mississippi, and extreme west Florida. A distinct summer
rainfall peak occurs along the Atlantic Coast, being most pronounced in
Florida. A secondary rainfall peak in March becomes pronounced along the
Gulf Coast. Fall is the driest season of the year, although droughts during
the growing season are not unusual."
Soils and Topography
According to Boyer (1990) : "Longleaf pine is native to a wide variety
of sites ranging from wet, poorly drained flatwoods to dry, rocky
mountain ridges. Elevations range from barely above sea level near the
beaches on the lower Coastal Plain up to about 600 m (1970 ft) in the
mountains of Alabama. Most of the longleaf pine forests are found on the
Atlantic and Gulf Coastal plains at elevations below 200 m (660 ft).
Here the soils are largely derived from marine sediments and range from
deep coarse, excessively drained sands to poorly drained clays. For the
most part, surface soils are sandy, acid, low in organic matter, and
relatively infertile."
Three soil orders are associated with longleaf pine. The first,
Ultisols, are the most expansive in the southeast, excluding peninsular
Florida. Entisols make up the Sandhills of the southeastern Atlantic
states. Spodosols, which are wet sandy soils,
have a fluctuating water table near the ground surface during rainy seasons.
This soil is common to
flatwood sites of the lower Coastal Plain of Florida.
Forest Associates
According to Boyer (1990) : "The principal longleaf cover types are Longleaf Pine (Society of
American Foresters Type 70), Longleaf Pine-Scrub Oak (Type 71), and
Longleaf Pine-Slash Pine (Type 83). Longleaf pine is also a minor
component of other forest types within its range: Sand Pine (Type 69),
Shortleaf Pine (Type 75), Loblolly Pine (Type 81), Loblolly
Pine-Hardwoods (Type 82), Slash Pine (Type 84), and South Florida Slash
Pine (Type 111).
"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
(Type 80). On poor, dry sandhillls 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.
"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 (Ilex coriacea),
buckwheat-tree (Cliftonia monophylla), blueberries, and
blackberries."
Habitat Competition
According to Boyer (1990) : "Longleaf pine is intolerant of competition, whether for light or for
moisture and nutrients. The species will grow best in the complete
absence of all competition, including that from other memebers of the
species. Fortunately, as noted earlier, young even-age longleaf pine
stands break up rapidly into a broad range of size classes, due to
variability in duration of the grass stage. Stagnation is almost never
a problem. However, even suppressed trees in a stand will slow the
growth of dominant neighbors. Optimum stand density for development of
crop trees needs to be maintained by periodic thinning. Given release
from neighboring trees, dominant and codominate trees in an over-dense
stand will respond promptly with increased diameter growth, as will some
intermediate trees that retain crown ratios of 30 percent or more.
Suppressed trees, while they may continue to live, rarely respond to
release with improved growth."
Hybrids
According to Boyer (1990) : "The major southern pines, as well as some minor species, are closely
related and have overlapping ranges. Natural hybridization has
contribute to genetic diversity among trees and populations. Natural
hybridization is common between longleaf and loblolly pine, producing the
Sonderegger pine (Pinus × 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 corssing. Natural
hybridization between longleaf and slah pine is unlikely, based on
differences between the species in dormancy and heat requirements for
flowering.
"Artificial crosses between longleaf pine and both loblolly and slash
pines can be achieved easily. Crosses between longleaf and shortleaf pne
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."