A longleaf pine is a species of pine tree that grows natively in the United States. Mature longleaf pine trees frequently exceed 100 feet (about 30 meters) in height. This tree gets its name from its long needles. These can grow to a length of 18 inches (about 45 centimeters), which is longer than the needles of any of the other species of American pine tree. These characteristic needles grow in clumps of three, are dark green in color, and often twist as they grow.
Prior to human habitation, much of the southern part of the United States was covered with a vast longleaf pine forest. These trees were exploited by early settlers for wood and later for shipbuilding. Years of land clearing and logging activities have meant that the modern day distribution of the long leaf pine is much more modest. The longleaf pine is still a common tree, however, in many of the southeastern states.
The bark of the mature longleaf pine tree is a red-brown color, and in texture, it is scaly and thick. This is believed to be an adaptation to protect the adult tree from fire. The young tree also has special adaptations to protect it from fire damage. In contrast to the growth patterns of most types of pine tree, the young longleaf pine does not rapidly elongate. Instead, it grows into a dense, bush-like cluster during the first three to seven years, which is called the ‘grass-stage’ of the longleaf pine.
The density of growth that is exhibited by young longleaf pines means that they can withstand a certain amount of the heat and damage from forest fires. In addition, the buds of the young tree are protected with long, thick, silver-colored hairs that reflect heat and guard the sensitive inner bud from heat damage. These important buds have an extra layer of protection, as they are surrounded by dense, moist needles. If these needles burn, they release moisture to protect the central bud, so that, as long as the fire passes quickly, the bud will survive, and the young tree can continue to grow. With these adaptations, longleaf pine forests can recover relatively well from forest fires, as long as the intensity of the fires is not too high.