Wildfire-Induced Mortality of Woody Plants in a Central Texas Savanna
Date
2004-05
Authors
Elliott, Kristine Gayle
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Abstract
Historically, the vegetation of the Edwards Plateau was probably a mosaic of grassland, savanna parkland and woodland. Over the last two centuries, woody plants have expanded into areas that were previously grassland, in part because of over grazing and fire suppression. Prescribed fires during the cool season have been used to restore grasslands in this region, but less is known about impacts of warm season fires on these savannas. I examined effects of a warm season wildfire on the mortality of woody species in four habitats (savanna parklands, woodlands, and north and south facing slopes) in an eastern Edwards Plateau savanna. I addressed the following questions: 1) How did the population structure of the woody species in each habitat change because of the fire? 2) Was woody plant mortality size and species dependent? Overall, fire-induced mortality was greatest in the open parkland (40.0%, p = 0.004) and lowest on the densely wooded south facing slopes (10.6%). Across all species, mortality was negatively related to plant height (p = 0.016, r2 = 0.836), and basal diameter (p = 0.003, r2 = 0.596). Out of the 23 species inventoried, mortality was greatest for Juniperus ashei (p < 0.05). Results indicate that warm season fires have the potential to significantly decrease woody abundance in these savannas, however effects vary with habitat, plant size and species. Thresholds may exist that limit the efficacy of hot, summer fires in restoring these savannas to pre-settlement conditions.
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Keywords
woody plants, Central Texas, wildfires
Citation
Elliott, K. G. (2004). Wildfire-induced mortality of woody plants in a central Texas savanna (Unpublished thesis). Texas State University-San Marcos, San Marcos, Texas.