As the name implies, longleaf pine has the longest needles of any native North American pine. The needles grow in bundles of three and can reach a length of 18 inches and gracefully droop from course, stubby branches of a mature tree. New seedlings don't put a lot of effort toward quick growth and can stay in a "grass stage" for a decade or more.
Longleaf pine seedlings form into clumps of long, green "needles" and stay in this protective state for several years. This mass of green needles help the tree survive in competing grasses that are prone to fire during dry periods. This "grass" stage of a young longleaf pine protects the tree and makes it the most fire-resistant of all the pines.
Forestryimages.org provides several images of parts of longleaf pine. The tree is a conifer and the lineal taxonomy is Pinopsida > Pinales > Pinaceae > Pinus palustris P. Mill. Longleaf pine is also commonly called longleaf pine, longleaf yellow pine and southern yellow pine.
3. The Range of Longleaf Pine
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.
Remarks: "Pinus palustris is adapted to frequent low intensity fire. Relevant adaptations include: * a deep taproot and a definite grass stage, which permit seedlings to lose foliage and yet survive low intensity fires (an adaptation also found in various other pines, notably P. engelmannii in Arizona); * profuse production and shedding of needles and ready shedding of lower limbs, which provide a rapid accumulation of fine fuels, sufficient to support ground fires at frequencies as often as 3 years; * an extremely flammable heartwood and sapwood shielded by a relatively fire-resistant bark. Consequently, snags and large dead wood accumulations are rare. Pinus palustris is adapted to frequent low intensity fire."
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. The bud also has scales for protection and a silvery pubescence that probably reflects heat.