Date of Award
Doctor of Philosophy - Forestry
Brian P. Oswald
Alyx S. Frantzen
East Texas’ diverse landscape can present year-round wildfire seasons that can be influenced by seasonal and regional differences in climate and physiography. Greater insight into the fundamental thermal behavior of wildland fuels can aid in fire behavior prediction and development of fire-resistant plant lists. This study focused on estimating seasonal and regional flammability characteristics of five evergreen species: yaupon (Ilex vomitoria), Chinese privet (Ligustrum sinense), greenbrier (Smilax spp.), eastern red cedar (Juniperus virginiana), and escarpment live oak (Quercus fusiformis); and two deciduous species: Chinese tallow (Triadica sebifera) and southern red oak (Quercus falcata). Live foliar and small diameter branch wood samples were collected in the Pineywoods, Post Oak Savannah, and Blackland Prairie Ecoregions during the dormant (February) and growing (August) season. Oxygen bomb calorimetry (OBC) and proximate analyses estimated ash-free net heat content (NHC-AF; MJ kg-1) and proportions of volatile matter (VM%), fixed carbon (FC%), and ash percent (ash%). Pyrolytic and oxidative thermogravimetric analyses (TGA) estimated model-free activation energies (Ea(s)), relative spontaneous ignition temperature (RSIT; °C), gas-phase maximum mass loss rate (GP-MMLR; % min-1), and gas-phase combustion duration (GP-CD; min.). Greater mean VM% was a general indicator of greater mean NHC-AF(s) and GP-MMLR(s). All foliar NHC-AF(s), RSIT(s), and GP-MMLR(s) were significantly different with respect to species, season, and ecoregion. Mean regional GP-MMLR(s) were consistently greater in the growing season. The Post Oak Savannah and Blackland Prairie consistently yielded species with the greatest mean NHC-AF(s) and oxidative TGA values. Mean Ea(s) did not present any significant seasonal or regional trends.
Tiller, Michael, "SEASONAL FLAMMABILITY COMPARISONS OF NATIVE AND EXOTIC PLANTS IN THE POST OAK SAVANNAH, BLACKLAND PRAIRIE, AND PINEYWOODS ECOREGIONS OF TEXAS" (2021). Electronic Theses and Dissertations. 417.
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