A Generational Change in Site Index for Naturally Established Longleaf Pine on a South Alabama Coastal Plain Site

Abstract

Abstract Research on longleaf pine (Pinus palustris Mill.) has been carried out for over 50 yr on a coastal plain site in south Alabama. Studies have included the original second-growth stands and also naturally established third-growth stands. Site index data revealed that estimated site index values for third growth generally exceeded those for second growth. Age 50 site index in 16 study compartments with second growth near index age averaged 66 ft. Estimated site index for third-growth stands recorded in 17 different compartments averaged 81 ft. Nine of the 16 compartments with second-growth stands now include third growth about 40 yr in age. This provided an opportunity to make a direct comparison of generational site index differences within the same compartments. Site index for second growth averaged 65 ft (range 61 to 70 ft), while third growth averaged 83 ft (range 77 to 87 ft). Reasons for this large increase in apparent site quality are unknown, but since soils are the same, some climate changes may be suspect. South. J. Appl. For. 25(2):88–92.