Feelin’ fine as longleaf pine

*Blog written by Plant Records Curator Pat Lynch

Longleaf pine (Pinus palustris) is the legendary southern yellow pine of the old south, ranging from southern Virginia south to central Florida and west to eastern Texas. The tall, stately longleaf pine once covered approximately 90 million acres of the southeastern United States Coastal Plain (Figure 1), but 200 years of logging and land clearing have reduced it to about three million acres. In recent years, about 1.5 million acres have been restored, with some of that restoration having taken place at Bok Tower Gardens. Longleaf pine can routinely live to 300 years old, but can take 100 to 150 years to reach mature size.

Unlike most pines, the first 3 to 7 years of longleaf pine growth do not involve trunk formation. Rather, it remains a fire resistant, trunk-less, cluster of needles resembling tufts of grass. During this period (referred to as the grass stage), seedlings are developing a deep taproot below ground and are capable of sprouting from the root if the top is damaged. Once the root system is thoroughly established, the tree begins to produce a trunk. This developmental period immediately following the grass stage is called the bottlebrush stage, as young seedlings resemble an elongate bottlebrush. Many also informally refer to this period as the “cousin itt” stage, as branchless seedlings often resemble the character from the Addams Family. Young longleaf pines at this stage are more susceptible to fire damage as their bark is still developing. Once plants reach approximately 8’ in height, the bark begins to thicken, forming large reddish-brown scales or plates that help insulate trees from heat and fire, and plants once again become strongly fire resistant.

Like all true pines, longleaf pine is a gymnosperm, which literally means naked seed (i.e., the seed is not enclosed within a fruit). Fruits comes from flowers and gymnosperms are not flowering plants; rather, they produce cones. Both male (Image 1) and female (Image 2) cones are initiated during the growing season before buds emerge. Male cones begin developing in July, while female conelets (Image 3) are formed during August. Pollination occurs early the following spring.

Like slash pine (Pinus elliottii), longleaf pines were a major resource for naval stores – resin, turpentine, and timber – needed by merchants and the navy for their ships. While America was still a British Colony, certain longleaf pine stands were reserved by the English crown to supply masts for sailing ships. The wood was also used in building and the sap was used in the turpentine industry. Instead of replacing slow growing longleaf pines after logging, faster growing slash and loblolly pine (Pinus taeda) were planted instead. Consequently, stands of old growth (i.e., mature) longleaf pine are extremely rare, as are many of the plants and animals that rely on this habitat.

Old-growth longleaf pine stands are the preferred habitat of the endangered red-cockaded woodpecker, (Picoides borealis), which nests in cavities that it excavates in the trunks of living pines. The rarity of old-growth stands has led to designation of the woodpecker as endangered. Conservation efforts aimed at saving the red-cockaded woodpecker have been a primary driver behind attempts to preserve the remaining old-growth stands. However, frequent low-intensity fire is critical to maintaining this habitat; in the absence of fire, longleaf stands succumb to understory invasion from turkey oak (Quercus laevis), blackjack oak (Q. incana) and even live oak (Q. virginiana). These species produce dense understory shade, preventing the establishment of pine seedlings, and they compete directly with adult pines for water and nutrients. Experts agree the preservation and restoration of longleaf pine habitat is dependent upon a frequent low-intensity fire regime, which has historically been at odds with prevailing views on forest management and fire suppression.

A wide variety of wildlife depends on longleaf pine habitat. Gopher tortoises, Florida mice, gopher frogs, and eastern diamond-back rattlesnakes are among the native animals that inhabit these ecosystems. The seeds are an excellent food source for squirrels, turkey, quail, and brown-headed nuthatches. The U.S. Fish and Wildlife Service lists 29 threatened or endangered species that rely entirely, or in part, on longleaf pine habitat. It is incumbent upon us all to ensure their continued survival.