Slash pine

Pinus elliottii
Family: Pinaceae

Natural Historyslash pine branch
Needles and cone of slash pine
Photo credit: Larry Korhnak, University of Florida

Because of its rapid growth rate, slash pine is a valuable tree for reforestation projects and timber plantations throughout the southeastern United States. As a result, slash pines are currently planted, grown, and harvested over millions of acres. The trees take 30 years to reach sawtimber size (greater than 9 inches in diameter). A good site can produce a well-stocked stand of about two cords of wood per acre per year.

There are two varieties of this tree species, slash pine (Pinus elliottii var. elliottii) and southern (or south Florida) slash pine (Pinus elliottii var. densa). The two varieties differ not only in geographical location, but also in seedling development and wood density. Southern slash pine is of denser wood and, unlike the slash pine, undergoes a grass stage.

Slash pine is a common associate of loblolly pine (Pinus taeda). The length and number of needles per fascicle, cones, and bark can be used to differentiate them. Slash pine has "brooms" of needles at the ends of rough twigs. Needles may be 5 to 11 inches long and are borne 2 to 3 to per fascicle. Cones range from 5 to 8 inches in length. Loblolly has 3 needles per fascicle that are 6 to 10 inches long. Loblolly cones are 3 to 6 inches long, but they are light reddish-brown and persist for three years of growth. Also, loblolly cones are far pricklier than slash pine cones. Bark of slash pine has large, flat, orange-brown plates. Loblolly bark is thick and divides into irregular, dark brown scaly blocks.

Habitat & Range

Slash pine is naturally found in wet flatwoods, swampy areas, and shallow pond edges. It can also occur in the low sandy soils that are poor in nutrients. It is very aggressive and commonly occupies cutover lands formerly occupied by other species. Slash pine (Pinus elliottii var. elliottii) is found in the Coastal Plain through north and central Florida. Southern slash pine (Pinus elliottii var. densa) is found in south Florida, West Indies, Guatemala, and Honduras in Central America.

Wildlife Use

The seeds of slash pine are an excellent food source for gray and fox squirrels and wild turkey.

Human Use

Historically, slash pines were a major resource for the naval stores industry. Pines produced turpentine and crude rosins that were used for a variety of purposes. Although the naval stores industry has all but disappeared from Florida, you can still find old slash pine stands with "catface" scars. The gum tappers formed the scars by injuring the tree with a triangular cut in the bark surface. While insects and disease can damage healthy slash pine stands, trees with "cat-face" scars are more susceptible to pine bark beetles and are vulnerable to mortality due to fire. Today, the species is dominant in the timber industry of the Southeast. The wood of this tree is used for railroad ties, fuel, lumber, and pulp.  It is often used as a roadside ornamental in several areas of the Deep South. 


 

Identifying Characteristics

Size/Form: Slash pine is a medium to large tree that reaches heights of 35 to 40 meters, with a trunk up to 1 meter in diameter. It is characterized by a long, clear, symmetrical bole, a deep root system, “brooms” of needles at the ends of the branches, and a dense, round-topped crown of horizontal and ascending branches.
Leaves:
Pines have long needle-like leaves that are held in bundles called "fascicles" with a sheath holding the needles together at the base. The first steps toward identifying each species are 1) measuring the length of the needles, 2) counting the number in a fascicle, and 3) measuring the length of the sheath. Be sure to check a few branches to get an average for the whole tree.

On slash pine, the needles are 15 to 25 cm long, and can be borne either in fascicles of 2 or in fascicles of 3. (In south or central Florida, the trees have almost entirely 2-needle fascicles. In northern Florida the trees have a mixture of 2-needle and 3-needle fascicles.) The needles are yellowish-green to bluish-green, stiff, and slightly twisted. They last 2-3 years on the tree. The needle sheath is 1-2 cm long.

Twigs: The twigs are orange-brown and stout (0.7 cm), becoming slender towards the tip.
Bark: The orange-brown bark is deeply furrowed on young stems, becoming 1 to 2 inches thick and broken into large, flat plates, covered with large, thin, papery scales.
Cones:
All pines are gymnosperms, which means that they reproduce with seeds but do not bear flowers or fruits. All pines are also monoecious, meaning that they bear both seed and pollen cones in separate structures on the same plant. The seeds cones can be "serotinous" (meaning that they remain closed at maturity and only open in response to a fire) or they can be "nonserotinous" (meaning that they open to release the seeds as soon as they are mature).

On slash pine, the pollen cones are 3-5 cm long and dark purple.

The young seed cones are pinkish and are commonly solitary. Mature seed cones are 7-15 cm long (rarely up to 20 cm long) and shiny reddish-brown. The exposed part of each scale forms a fairly flat diamond shape that is crossed by a low ridge with a short, stout, straight spine in the middle. Slash pine seed cones are generally serotinous, but it can be variable.

Seeds: The seeds of slash pine are 6-7 mm, with an attached wing adding 13-20 mm.
Similar Trees on the Florida 4-H Forest Ecology Contest List:
There are four pine species on our list.
  • Loblolly Pine has needles in fascicles of 3. The needles are 4 to 9 inches long.
  • Longleaf Pine has needles in fascicles of 3 or occasionally 4. The needles are 8 to 18 inches long.
  • Pond Pine has needles in fascicles of 3 or occasionally 4. The needles are 4 to 8 inches long.
  • Slash Pine has needles in fascicles of 2 or occasionally 3. The needles are 5 to 12 inches long.

 

Images

Click on any thumbnail to see a photo. Use left and right arrows to navigate. Use "esc" to exit the lightbox.

 

Learn More