Effects of forest fire disturbance on non-structural carbohydrates and carbon, nitrogen and phosphorus of Pinus yunnanensis

The organ-level effects of wildfire on plant nonstructural carbohydrates (NSC) and stoichiometric characteristics are poorly understood. We studied the effects of fire on sugar, starch, carbon (C), nitrogen (N), and phosphorus (P) content in the needles, branches, stems, and fine roots of fire-damaged Pinus yunnanensis trees (F-trees). Starch, sugar, and NSC content were higher in the roots and needles of F-trees than that of undamaged individuals (H-trees). C, N, and P content and stoichiometry characteristics of F-trees also differed significantly from H-trees. The N/P content of both F-tree and H-tree needles were < 14 prior to forest fire disturbance and increased thereafter, indicating that N limitation increased after fire disturbance. In addition, F-tree physiology did not return to control levels nine months after fire disturbance, indicating that more time is needed to recover. These findings suggest that forest management practices that increase soil N content will likely accelerate post-fire recovery. Because fire frequency and intensity will continue to increase in response to climate change, our results are of great value in improving our understanding of post-fire ecosystem dynamics.