What 45 years of RLGS data has to say about longleaf pine mortality - not muchThis article is part of a larger document. View the larger document here.
The original longleaf pine (Pinus palustris Mill.) forest was self-perpetuating where seedlings always had to be present. It reproduced itself in openings in the overstory where dense young stands developed. These openings would range from a few tenths of an acre to large openings of several thousand acres. Regardless of the event size, longleaf pine was able to regenerate these openings. In 1964, the USDA Forest Service established the Regional Longleaf Pine Growth Study (RLGS) in the Gulf States. The original objective of the study was to obtain a database for the development of growth and yield predictions for naturally regenerated, even-aged longleaf pine stands. The study has been expanded over the decades to examine numerous aspects of longleaf pine stand dynamics. Landowners who have stands of large/old longleaf pine trees have fears they will lose them to some type of mortality before they can harvest them. For over 4 decades, the amount of mortality and its cause have been documented for the trees in the RLGS. One of the major causes of mortality has been suppression that happens among the smallest trees or trees that have been over-topped for several years. At the other end of the tree size class, larger trees are killed by lightning strikes. These events are low level and happen at low frequencies every year. Surprisingly, despite being among the most fire-adapted tree species in nature, fire can kill longleaf pine. So what kills longleaf pine trees and how often does it happen?