Fire-Induced Changes in Quercus Laevis Spatial Pattern in Florida Sandhills

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Abstract
The influence of fires on spatial pattern of Quercus laevis (turkey oak) growing on xeric sandhills in Florida was analysed using second-order L(t) functions. Monte Carlo tests were used to evaluate whether the observed patterns differed from complete spatial randomness and whether changes in pattern could be explained by random fire mortality. Q. laevis trees in unburned sandhills were slightly clumped to randomly distributed at most scales. Initial fires tended to reduce the scale of maximum clumping, increase clumping intensity, create a more random to regular pattern at large scale, and increase segregation of Q. laevis and Pinus palustris (longleaf pine). Repeated fires at one-, two- and five-year intervals eventually left only a few clumps, which were protected from P. palustris along plot edges or near Q. geminata (sand live oak) groves. In a reference plot unburned for twenty-one to twenty-five years, Q. laevis became more randomly distributed at all scales over a four-year period, and became slightly more aggregated with respect to P. palustris. Patchiness of Q. laevis surviving fires was probably related to spatial variation in fire intensity, particularly with ''hotspots'' around P. palustris and protected areas near Q. geminata.