Longleaf Pine

Longleaf pine (Pinus palustris; figs. 1 through 5) is an iconic tree species native to the southeastern United States. Before the arrival of non-Indigenous settlers, longleaf pine occurred as the dominant tree species across an estimated 29.9 million ha (73.9 million acres) of fire-maintained forests, woodlands, and savannas, and another 7.3 million ha (18 million acres) as a codominant in mixtures with other fire-adapted tree species (Frost, 1993). Over the next three centuries, a combination of anthropogenic factors decimated longleaf pine and its associated ecosystem (Frost, 2006). Longleaf pine was initially harvested by settlers to clear land for agriculture and provide material for housing and fencing. In the early to mid-19th century, vast areas of longleaf pine were killed in turpentine orchards to supply the naval stores industry. Near the turn of the 20th century, steam-powered technology drove decades of extensive logging throughout much of the remaining longleaf pine woodlands. Recovery from exploitation was hindered by regeneration failures deriving from local seed source limitations, seedling depredation from introduced hogs, fire exclusion, and land use conversion. Longleaf pine continued to decline gradually until the 1990s, when existing extent reached its nadir of approximately 1.2 million ha (3 million acres) (Outcalt and Sheffield, 1996). Subsequently, concerns over the loss of habitat for several endemic flora and fauna prompted extensive investment and research into restoring the longleaf pine ecosystem (Landers et al., 1995). Contemporary restoration efforts have succeeded in stemming the loss of longleaf pine extent and have even produced a modest recovery. However, at the current estimated extent of 1.8 million ha (4.4 million acres), restoration remains a work in progress (Oswalt and Guldin, 2021). Longleaf pine is preferentially grown for its ecological, economic, and social values. Ecologically, longleaf pine is considered a foundational species in southeastern woodlands for its role in promoting understory flammability (Varner et al., 2021a). Longleaf pine is also well adapted to resist disturbances such as drought and wind, which are common throughout the region (Rutledge et al., 2021; Samuelson et al., 2019). From an economic perspective, longleaf pine is often commercially grown for sawtimber or utility poles, while its straw is highly sought as groundcover in the landscaping industry (Dickens et al., 2012; South, 2006). Beyond its ecological and economic importance, longleaf pine is viewed by many throughout the region as a cultural symbol connecting humans to their local environment (Gordon et al., 2020).