Longleaf Pine (Pinus palustris Mill.) Branch Pruning by Prescribed Fire

Efforts to restore longleaf pine (Pinus palustris Mill.) in the southeastern US require substantial artificial regeneration. Once established, important questions remain about when to introduce fire. We investigated the impact of initial planting density on tree branching and how prescribed fire might interact with tree architecture and survival. A particular focus was on how prescribed fires could prune lower branches. Lower density plantings (897 trees ha(-1)) had more and larger live lower branches than higher density plantings (2,243 trees ha(-1)). Fire was effective in pruning lower branches regardless of season burned, but fire in the growing season was more effective at pruning. Branches up to a height of 1.5 to 2 m were killed by fire. Fire applied in August caused greater damage with more needles scorched and/or consumed and more stem char. Prescribed fire did not impact longleaf pine tree survival. In general, fire applied to longleaf pine facilitated pruning lower branches that affect long-term wood quality, an additional argument for its utility in restoration and management of these ecosystems.

Automated summary

Research showed that longleaf pines planted at lower densities had more and larger live lower branches compared to higher density plantings. Prescribed fires were effective in pruning lower branches, with fires in the growing season being more effective. The fires did not impact the survival of longleaf pine trees.