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The recent surge in fire activity and the extent of displaced communities as a result of wildfire has increased awareness of wildfire issues nationwide (Syphard et al., 2017). Climate change, population growth, and continued development in the wildland urban interface (WUI) has contributed to a growing body of research into the underlying causes of this continued destruction (Kramer et al., 2019). There is no doubt that statewide policies, such as defensible space or building regulations, are associated with home survival (Keeley & Syphard, 2019). However, the relative effectiveness of wildfire mitigation depends on a myriad of factors specific to individual communities impacted by wildfire. This study focuses on factors that contributed to structure loss as a result of the 2017 Thomas Fire in Ventura, CA. Through spatial analysis utilizing GIS software, we were able to determine that defensible space played a minimal role in structural survivability during the Thomas Fire. Our research shows that fence type (noncombustible, combustible, or none) is a more significant factor at decreasing the odds of structure loss for homes experiencing wildfire under similar conditions. Effective wildfire mitigation relies on multiple factors, and government agencies must take a holistic approach rather than singular, “one size fits all” approaches to reduce the impact of future catastrophic wildfire.

Greater numbers of people are moving into wildland-urban interface (WUI) areas, increasing the number of people at risk to large wildfires. To mitigate the hazard, emphasis is often placed on fuel treatments used to reduce fuel loads and subsequent fire behavior. This approach overlooks the additional benefits provided by vegetation, including carbon storage and sequestration along with air pollutant removal. This study aimed to calculate and compare differences in representative values by examining a study site in the Klamath Mountains of Northern California. Fire behavior simulations were done under various weather scenarios to illustrate both the impact of weather on fire intensity as well as the limitations of various fuel treatments. Ecosystem services were modeled using the I-tree Eco software (formerly the Urban Forest Effects model). Results showed a reduction in surface and an increase in canopy base height from the treatments and subsequent reductions in fire intensity under moderate and high conditions with the largest difference occurring in the Thin + Fire treatment. Under extreme weather conditions, the effectiveness of all fuel treatments was reduced. Ecosystem services showed a reduction of carbon sequestration in the fuel treatments corresponding to the reduction of smaller diameter trees from the fuel treatments. The greatest difference occurred in the Thin + Fire treatment. These results and the methods used to acquire them show the impacts from fuel treatments can be characterized and compared. This information will allow land managers to make decisions that account for a variety of considerations, while also providing them with tools that can facilitate the cooperation and collaboration of multiple stakeholders.

Since 1990, thirteen fires over 100,000 acres in size have burned in California seven of which were recorded to be some of the most destructive wildfires of all time (California Department of Forestry & Fire Protection 2013). To aid the development of policy that reduces the destruction caused by wildfires, it is important to evaluate how risk changes through time in communities that are expanding into fire-prone areas. The objective of this study is to discover how the likelihood of structural loss is changing in WUI as newer; more fire resilient structures replace older structures on the edges of the WUI. Geographical Information Systems and remote sensing techniques were used to observe changes in urbanization, structural materials, housing density and defensible space over time in the communities of Rancho Santa Fe, Ramona and Julian in San Diego County. Fire Risk ratings were calculated using the equation Fire Risk= Hazard – Mitigation. Mitigation scores for each structure were informed using a binary logistic regression of variables influencing home loss in the Witch Creek Fire. Fire Risk Ratings were given to the 11,747 structures in the three communities for the years 2005, 2009, 2010 and 2012. The study found that the initial 0-1.5m zone around the home is the most critical for defensible space. In this zone, increased tree cover increases the odds of structure loss by over double that of grass cover. In Rancho Santa Fe and Julian, the majority of very high risk homes were located in high income communities despite moderate mitigation due to very high fire hazard levels. In Ramona most very high fire risk homes were located in lower income areas due to poor mitigation levels. Rancho Santa Fe and Julian decreased their fire risk over the 7 year study period with improved mitigation, Rancho Santa Fe improved the most (1.7% decrease in Very High and High risk homes). The proportion of very high fire risk homes increased in Ramona by .5% over the 7 year study period. Development on the outskirts of the WUI could increase the risk of the overall community if proper construction standards are not met and defensible space is not implemented. If fire resistant communities are constructed and maintained to high standards of defensible space, they could potentially provide a buffer for older high fire risk homes.

Rosebay rhododendron (Rhododendron maximum L.) is an ericaceous shrub commonly found in riparian areas of the Appalachian Mountains. After more than a century of fire exclusion in the U.S., the distribution of R. maximum and its dominance of forest understories have increased. Rhododendron expansion has caused a decline in overstory regeneration and the potential for dangerous fuel conditions around suburban structures near the wildland-urban interface. The purpose of this study was to determine the effects of seven silvicultural treatments on both the fuel loading within an R. maximum thicket and the control of R. maximum as a forest weed. The final objective of the project was to determine the cost effectiveness of each implemented treatment. Due primarily to moisture conditions, a single prescribed burn was relatively ineffective in reducing fuel loading and causing R. maximum mortality. Mechanical cutting caused a drastic shift in the size-class distribution of R. maximum but resulted in heavy sprouting and increased fuel loading. Herbicide application did not reduce or increase fuel loading and was important in R. maximum control only when combined with other treatments. The prescribed burning treatment was the least expensive individual treatment while mechanical cutting was the most expensive. Combination treatments showed increased effectiveness in controlling R. maximum but were more expensive than the individual treatments. The results of the treatments from this study will be used over the long term to demonstrate to land managers the effects of vegetation control on rhododendron. / Master of Science

abstract: Increasingly, wildfires are threatening communities, forcing evacuations, damaging property, and causing loss of life. This is in part due to a century of wildfire policy and an influx of people moving to the wildland urban interface (WUI). National programs have identified and promoted effective wildfire mitigation actions to reduce wildfire risk; yet, many homeowners do not perform these actions. Based on previous literature and using the theory of planned behavior (TPB), this study proposes an integrated wildfire mitigation behavioral model to assess and identify the factors that influence homeowners’ wildfire mitigation behaviors. Specifically, the study tests the validity of the theory of planned behavior as a foundational model in exploring wildfire mitigation behaviors, develops and empirically tests a wildfire mitigation behavioral model, and explores the role of homeowner associations (HOA) on wildfire mitigation behaviors. Structural equation modeling was used on data collected from homeowners with property in the WUI in Prescott, Arizona. Results suggest TPB provides an acceptable model in describing homeowner wildfire mitigation behavior. For HOA residents, attitudes toward wildfire mitigation behaviors play an important role in predicting intentions to perform these behaviors. Additionally, perceived constraints directly influenced actual mitigation actions. For non-HOA residents, subjective norms influenced intentions to mitigate. Implications for research and local wildfire mitigation programs and policy are discussed. / Dissertation/Thesis / Doctoral Dissertation Community Resources and Development 2016

The average intensity and frequency of wildland fires have been on the rise over the years, leading to an increase in the risk to homes located in the Wildland-Urban Interface (WUI). Fire suppression is the most used method of wildland fire control, but this suppression can cause wildland fires to become more frequent and devastating. Increased development in the WUI also puts these homes at greater risk. Current methods of passive fire protection are effective, but these methods are expensive, time consuming to set up, and not fully effective. This research proposes a permanent passive fire protection system that is built into the structure. A flame- resistant material would be attached to the sheathing with the roofing and siding attached over the material. This system would allow the easily replaceable exterior components of the structure to burn, and the interior of the structure would be protected. This system protects the structural supports of the building, so the house does not collapse, and the exterior components can be replaced. To test this permanent passive fire protection system 21 small-scale specimens were constructed with five different flame-resistant materials and three different types of siding. The flame-resistant materials include structural wrap, Kaowool, ceramic fiber insulation, Pyrogel, and intumescent paint. The sidings include wood siding, vinyl siding, and hardie board. The testing took place in a burn room to simulate the conditions of a wildland fire. Post-burn charring evaluations and temperature analyses were conducted to determine which type of material and siding were most effective at protecting the small-scale models. The charring evaluation included determining the percent charring of the OSB face of the specimens, and the temperature analysis included determining the percent difference between the internal and external temperatures of the specimens. The performance, cost and installation, constructability, and replaceability of each of the materials were considered in deciding which materials were most effective. Overall, the Pyrogel outperformed the other materials, but this material is by far the most expensive. The ceramic fiber material was overall the second most effective flame-resistant material, and this material could be as effective as the Pyrogel if used in conjunction with the other materials tested. Further testing of material combinations is required to determine if different flame-resistant material combinations could be as effective as the Pyrogel material on its own. The results of this project did prove the feasibility of a permanent passive fire protection system, but further testing of large-scale specimens is required to test the effectiveness of the system in more complex circumstances.

Human disruption of climate, habitat, and ignition has altered the behavior of wildland fire at local to continental scales. In many regions, novel fire regimes are emerging that threaten to exceed the capacity for local management to protect human wellbeing and ecosystem function. Simultaneous changes in climate, species composition, and fire management have resulted in extreme fire behavior in many regions. For the Western United States, the emerging novel fire regime consists of more frequent, severe, and intense wildfires, with annual area burned by wildfire having doubled and high-severity wildfire area having increased 8-fold since the 1980s. The impacts of these increasing stresses in the Great Basin is especially pressing when combined with the many years of historically poor resource management. Here we complete a literature review of changing wildfire regimes globally (chapter 1) and a study of how the abiotic and biotic aspects of aquatic ecosystems stabilize after a megafire in the western United States (chapter 2).

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A botanical inventory of Doe Mountain Recreation Area (DMRA) in northeastern Tennessee was conducted to help guide conservation-based management. A total of 484 species were found in DMRA, comprising 94 families, and 285 genera, 10 species listed in the state rare plant list, and 76 exotic species. Two species, Liatris virgata and Lycopodiella inundata, were new state records. Water in the Lycopodiella seep was an order of magnitude more acid than at other sites. An analysis of the wildland-urban interface showed that only 13% of the area was classified as uninhabited. The inventory-invasion index, introduced to quantify the relative degree of botanical uniqueness, was indicative of an under-explored or unique area but less so compared to some other botanically-rich regional sites. Management should aim to protect acid seeps, arid roadside slopes, curtail mowing a roadside that supports a state endangered species, and avoid herbicides in the biodiverse power line corridor.