Does frequent burning affect longleaf pine (Pinus palustris) bark thickness?

Bark thickness plays a critical role in protecting a tree's cambium from damage by fires. Does frequent surface fire stimulate bark production compared with a fire-suppressed control? Based on data from an ongoing, long-term prescribed fire study, we explored differences in bark thickness from 0 to 200 cm above the ground for longleaf pine (Pinus palustris P. Mill.) trees on burned and control sites. Biennial prescribed fires, applied between 1973 (stand age = 14 years) and 2006 (stand age = 47 years), significantly reduced diameter at breast height. After adjusting for differences in diameter at breast height, we found no difference in bark thickness of trees from the burn and control sites, except for bark thickness measured at 0 cm aboveground where control sites had significantly thicker bark than burned sites. Results suggest that frequent burning did not stimulate bark production in longleaf pine.