The extent of the longleaf pine (Pinus palustris Mill.) ecosystem has been dramatically reduced over the past 150 years throughout the southeastern USA, from a high of 37 million ha to a low of 1.5–1.7 million ha, currently. Most of this reduction has been caused by cutting, species replacement, and ineffective fire management. Several organizations have studied various means to restore and increase the area of this important southern pine ecosystem. One important component of this effort is to assess the amount of forest land with longleaf pine primary regeneration (seedlings <2.54 cm in diameter but ≥ 15 cm tall). We used data from the USDA Forest Service, Forest Inventory and Analysis (FIA) program, to determine the extent and condition of longleaf pine primary regeneration. Using the premise that all overstory stand components originated from the seedling stage, an evaluation of the seedling component of longleaf pine seedlings is important for evaluating and managing for the future sustainability of the ecosystem. Our assessment determined the amount of forest land with longleaf pine seedlings; the structural component was defined by seedling density, dominance, species richness (S), and evenness metrics. For the latter the McIntosh Evenness Index (MEI) was used.
Results/Conclusions
Across the coastal south, from North Carolina to Texas, 3,458,396 (±181,376 C.I.) ha of forest land contained at least 14 longleaf pine trees per ha (TPH) that were ≥2.54 cm dbh (one tree sampled per sample unit [SU]). In these longleaf pine forests there were 897,757 ha (±118,730 C.I.; n=483) with longleaf pine seedlings present; 57 percent on private forest land, 41 percent on public land, and 3 percent on forest industry land. Most of these seedling occurrences were in forest stands where trees ≥2.54 cm dbh were present. These stands had longleaf pine seedlings averaging 865 TPH, seedling (S) = 4.3 SU-1, and MEI= 0.67. Some newly established or regenerated forests (< 8 years old) with no overstory component were evident, approximately 216,751 ha (174,572 ha in plantations and 42,179 ha in natural stands). Here, density of longleaf seedlings averaged 904 TPH, seedling (S) =3.3 SU-1, and MEI= 0.59 while the proportion of seedlings in longleaf averaged 45 percent. Overall, the high (S) and MEI along with low TPH may indicate shortcomings in the primary regeneration of longleaf pine. The area in new longleaf stands is encouraging but the longleaf seedling metrics may indicate stands with inadequate stocking levels.