Fire and longleaf pine physiology-- Does timing affect response?

Southern pines vary in their response to the loss of leaf area by crown scorch. We hypothesize that they tolerate crown scorch by at least three recovery mechanisms, but the function of these mechanisms is season-dependent. Using sapling longleaf pine as a model and experimental results from central Louisiana, U.S.A., our objective is to present examples recovery from scorch, and discuss how this may be affected by season. Results indicate that longleaf pine health and sustainability may be dependent on this species’ ability to shift leaf area upward on the stem, rapidly re-establish leaf area with the mobilization of stored energy, and maintain high rates of net photosynthesis during the height of the growing season. However, the seasonal nature of carbon allocation to stored energy may interact with leaf area re-establishment to jeopardize sustained health and production. Keywords— biennial prescribed fire, leaf area, net photosynthesis, Pinus palustris Mill., root starch