As a response to rising wildfire hazard and forest structure and composition concerns, the National Fire and Fire Surrogate Study was established in 2000 to determine how fuel reduction and ecosystem restoration techniques might affect ecosystem properties and processes across the United States. Soil chemistry and the southern Appalachian Mountains were an ecosystem property and ecoregion of interest, respectively. Treatments utilized at this site included: prescribed fire alone (3 burns), mechanical cutting of understory shrubs and midstory trees alone (2 cuttings), and a combination of the two (2 installations). Soils were sampled in 2018 to determine potential treatment impacts for: O horizon and mineral soil (0-10 cm depth) carbon (C), nitrogen (N), carbon:nitrogen (C:N) and mineral soil calcium (Ca), magnesium (Mg), phosphorus (P), potassium (K), and pH. Results suggested slight, but statistically significant changes in O horizon C and N and mineral soil C, N, C:N, Ca, and P values from 2001-2018 differed statistically between the treatments. Soil responses differed significantly between the replications utilized in this study and also did not fully agree with results from previous sampling that occurred following the first implementation of these treatments. This research highlights the spatial and temporal nature of soil responses to management. When considered with previously reported vegetation and fuels results from this site, it appeared that prescribed burning with and without mechanical cutting presented the most promise to achieve ecosystem restoration and fuel reduction properties without altering forest soil chemistry. / Master of Science / Fire was historically present in the southern Appalachian Mountains from both natural and anthropogenic sources. A common natural cause resulted from lightning ignitions while some common anthropogenic sources resulted from Native American ignitions. Their fire-use goals included understory clearing, reduction of pests and diseases, hunting, and even warfare. These practices were adopted by early European settlers and were implemented regularly across the landscape through the late 19th century. In the early 20th century, however, fire exclusion policies were implemented across broad acreages of the continental United States. Over 80 years later, such policies led to forests that have been altered from their historic composition. Some of these alterations include changes to plant species composition. In portions of eastern United States forests, fire intolerant, shade tolerant species now exert a dominant influence beyond what would be expected in a frequently altered state. This process, referred to as mesophication, is a positive-feedback cycle that changes the composition of the forest floor, as well, as a result of the vegetative composition alterations. This cycle has led to substantial forest floor fuel accumulations comprised of vegetative litter and duff. Essentially, this policy shift and subsequent fuel alteration has potentially increased wildfire hazard when dry weather conditions and ignitions coalesce. In 2000, the National Fire and Fire Surrogate Study (FFSS) was designed and implemented to study ecosystem responses to fuel reduction treatments in 13 locations across the United States. One of these locations was the southern Appalachian Mountains near Hendersonville, North Carolina. For this particular study, soil chemistry was the observed ecosystem trait. The treatments included untreated control, prescribed fire, mechanical cutting of vegetation, and a combination of prescribed fire and cutting. From 2001-2018, 4 prescribed burns, 2 cutting treatments, and 2 combination treatments have been implemented. Prior to the first treatments in 2001, soils were sampled to determine pre-treatment soil chemistry. In 2018, soils were re-sampled to determine the potential long-term impacts of repeated implementations of these management techniques on forest soil chemistry. Overall, the results suggested that forest soil chemistry was altered in ways that do not appear biologically significant and may in fact fail to alter soils in ways that might benefit and sustain long-term ecological restoration objectives. Continued treatment applications may be necessary to obtain more desirable conditions.

Caldera systems such as Long Valley Caldera, California; Taupo, New Zealand; and Campi Flegrei, Italy, experience centuries to millennia without eruption, but have the potential for large eruptions. This raises questions about how local residents' behavioral responses to these low-probability high-consequence events differ from their responses to events, such as wildfires and earthquakes, that have higher probabilities. To examine this issue, a multi-hazard mail survey of 229 households explored perceptions of—and responses to—volcano, earthquake and wildfire hazards in the Long Valley Volcanic Region. Response efficacy was the only significant predictor of emergency preparedness, which suggests that hazard managers can increase household emergency preparedness by emphasizing this attribute of protective actions. In addition to response efficacy, expected personal consequences, hazard intrusiveness, and affective responses were all significantly related to information seeking. This indicates that hazard managers can also increase households’ information seeking about local hazards and appropriate protective actions by communicating the certainty and severity of hazard impacts (thus increasing expected personal consequences) and that they communicate this information repeatedly (thus increasing hazard intrusiveness) to produce significant emotional involvement (thus increasing affective response).

Wildfire hazard is increasing in much of the United States, posing a threat to human communities and natural ecosystem services, especially in areas at the wildland-urban interface. There are steps people can take to reduce wildfire hazard, but often they are not used. Understanding and addressing human perceptions of wildfire risk and of risk-mitigating behaviors requires knowledge of both social and ecological systems. To better understand this complex issue, three types of factors must be addressed: social, cultural, demographic, and biophysical. This dissertation incorporates these three essential factors to intensively investigate the risk perception and behaviors of residents living in wildland-urban interface communities in three states (Arizona, California, and New Mexico). The first study examines the effect that individual risk perceptions have on intention to mitigate wildfire risk by integrating two social-psychological theories, Theory of Planned Behavior and Cultural Theory, to investigate the causal relationship and motivational factors that influence the intention to mitigate wildfire hazard. Results suggest that attitudes toward wildfire mitigation practices and perceived behavioral control play a significant role in the decision process. The effect of an individual’s orientation toward nature is mediated by attitude and perceived behavioral control. It is important that these orientations are taken into consideration when designing strategies to increase incentives to mitigate fire risk. The second study explores the linkage between property owners’ perception of risk and scientifically measurable wildfire risks that vary across hazard zones in the three study locations. Individuals’ perceptions of wildfire can be substantially different from each other and from reality. This study proposes that the perception of risk is formed in a multistage process (individual and community level). Results show that homeowners’ worldview with respect to nature, length of residency, place-based influence, and attitudes about risk factors all are significant predictors for how residents of fire-prone areas perceive their risks. The variance in social and physical vulnerability associated with wildfire can explain, to a certain extent, the variation in individual perceptions of wildfire risk. The perception of risk is consistent with the level of exposure to fire hazards. The third study investigates spatial relationships among social and ecological factors on private property. The biophysical characteristics of individual properties were extracted to observe wildfire risk and incorporated with information about social context from mail surveys. Results demonstrate that mitigation behaviors in the three study communities illustrate a spatial clustering pattern. Moreover, orientations toward nature and physical attributes of property had an impact on decisions to undertake mitigation behaviors.