Abstract

Shortleaf pine is one of the most important trees in the southeastern United States for lumber, plywood, and pulpwood. Throughout its range, shortleaf pine is subjected to frequent fires that can be harmful to seedlings, often leading to death of the stem (top-kill). Frequent fire has led to the development of fire-adapted traits, specifically thick bark and sprouting from the basal crook after top-kill. The thick bark of shortleaf pine acts as a protective barrier for the cambium during a fire; while the basal crook is insulated from fire in the soil, protecting auxiliary buds that sprout after top-kill. Our study aims to determine what fire-adapted traits protect shortleaf pine throughout its life, from seedling to mature tree. We measured shortleaf pine sprouting after top-kill and the development of bark thickness in relation to stem size. We found defense mechanism varied by tree size: demonstrating a shift in fire-defense mechanisms throughout the life of the tree.