Poster Sessions Concurrent Sessions Conference Proceedings Oak Symposium Home This paper was not included in the Symposium Proceedings.	Pre-Symposium Abstract of Paper Long Term Monitoring of Coast Live Oak and Engelmann Oak Populations in San Diego County: 10 Years of Change Dawn Lawson Southwest Division, Naval Engineering Facilities Command, LawsonDM@efdsw.navfac.navy.mil, (619) 532-3775 Leslie Seiger San Diego State University, lseiger@sunstroke.sdsu.edu, (619) 594-6328 Paul Zedler University of Wisconsin-Madison, phzedler@facstaff.wisc.edu, (608) 265-8018 This study resampled plots in the Engelmann oak phase of southern oak woodland that were originally sampled ten years earlier. The data show a large increase in Coast Live oak saplings on a subset of plots, but a lesser increase in Engelmann oak saplings on those same plots. Previous studies have shown that Engelmann oaks were less successful in seedling establishment but had a higher survival into the larger size classes, apparently because of greater ability to survive in gaps. Recently acquired long term data suggest a more complex pattern of survival and growth in which growth was greater in gaps, but a greater number of saplings were found under the outer canopy of large trees than either under the inner canopy or in gaps. This pattern held for both species to different degrees. The new data suggest that factors explaining the coexistence of these two species may vary over time and are probably more complex than previously believed. These long term demographic data allow additional insight into patterns of establishment, growth and mortality and the coexistence of the two species.
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