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Florida 4-H Forest Ecology

Florida 4-H Forest Ecology

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 three. The needles are four to nine inches long.
  • Longleaf Pine has needles in fascicles of three or occasionally four. The needles are eight to 18 inches long.
  • Pond Pine has needles in fascicles of three or occasionally four. The needles are four to eight inches long.
  • Slash Pine has needles in fascicles of two or occasionally three. The needles are five to 12 inches long.

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