Wildfire and Postfire Restoration Action Effects on Microclimate and Seedling Pine Tree Survivorship

Abstract

Abstract Through modification of structural characteristics, ecological processes such as fire can affect microhabitat parameters, which in turn can influence community composition dynamics. The prevalence of high-severity forest fires is increasing in the southern and western United States, creating the necessity to better understand effects of high-severity fire, and subsequent postfire management actions, on forest ecosystems. In this study we used a recent high-severity wildfire in the Lost Pines ecoregion of Texas to assess effects of the wildfire and postfire clearcutting on six microclimate parameters: air temperature, absolute humidity, mean wind speed, maximum wind speed, soil temperature, and soil moisture. We also assessed differences between burned areas and burned and subsequently clearcut areas for short-term survivorship of loblolly pine Pinus taeda seedling trees. We found that during the summer months approximately 2 y after the wildfire, mean and maximum wind speed differed between unburned and burned areas, as well as burned and burned and subsequently clearcut areas. Our results indicated air temperature, absolute humidity, soil temperature, and soil moisture did not differ between unburned and burned areas, or burned and burned and subsequently clearcut areas, during the study period. We found that short-term survivorship of loblolly pine seedling trees was influenced primarily by soil type, but was also lower in clearcut habitat compared with habitat containing dead standing trees. Ultimately, however, the outcome of the reforestation initiative will likely depend primarily on whether or not the trees can survive drought conditions in the future, and this study indicates there is flexibility in postfire management options prior to reseeding. Further, concerns about negative wildfire effects on microclimate parameters important to the endangered Houston toad Bufo (Anaxyrus) houstonensis were not supported in this study.