PS 78-57 - Ten years of change in spatial pattern in an Oklahoma crosstimbers forest

Friday, August 12, 2011
Exhibit Hall 3, Austin Convention Center
Kelly A. McGrath1, José Ramón Arévalo2, Daniel J. McGlinn3, Matthew S. Allen1 and Michael W. Palmer1, (1)Botany, Oklahoma State University, Stillwater, OK, (2)Universidad de La Laguna, La Laguna, Spain, (3)Biology, Utah State University, Logan, UT

Crosstimbers represent a spatially extensive forest type in the southern Great Plains, and consist predominantly of Quercus stellata and Quercus marilandica. However, studies of dynamics based on permanently marked plots are lacking. We studied a 4ha Crosstimbers standin the Tallgrass Prairie Preserve in northern Oklahoma, tagging all trees greater than 2.5cm DBH, (7683 total) in 1998 and again in 2008. For each tree we recorded species identity, DBH, and spatial coordinates, and cored a subset of trees for age analysis. We then performed a modified Ripley’s K and O-ring statistic on the univariate and bivariate pattern for both all stems and each species at both time points.


The stand experienced an overall loss of ~1600 stems, a higher mortality rate for Q. marilandica, and a 13% increase in basal area for Q. stellata.  Q. marilandica suffered a 26% loss in basal area. Univariate analyses show clumping at smaller scales at both time points; bivariate analyses show relationships between clumping, stem size, and mortality. These early results illustrate surprising changes in forests that superficially appear to be unchanging, and highlight current questions about oak forest dynamics, including oak death and recruitment in a xeric, fire managed environment.

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