As the threat of wildfires in the United States increases due to global warming, understanding their effects on the soil biological community becomes central to recovery efforts. Therefore, it is important to study microbial community dynamics in forest soils impacted by fires from the view of elucidating how the new state compares with the original state of the microbial community. For this study, wildfires were hypothesized to cause a shift in the microbial community structure with dominant microbes being those best capable of responding to changes in their environment caused by the perturbation. The objectives of this research were to examine the recovery of the forest soil microbial communities after a wildfire and to investigate the state of the communities more than two years post-fire. After a wildfire occurred in the New Jersey Pinelands in 2007, soil samples were collected from the organic and mineral layers of two severely burned sites and an unburned control site over the span of two years following the fire. Microbial community composition was evaluated by principal component analysis and multivariate analysis of variance of molecular fingerprint data for bacterial, archaeal, and fungal-specific amplicons from denaturing gradient gel electrophoresis. The bacterial communities in the samples collected from 2 and 5 months following the fire clustered separately from those collected 13 and 17 months post-fire in two-dimensional space, indicating that the soil bacterial community structure changed with time following the fire. Deeper evaluation of the bacterial, archaeal, and fungal community patterns revealed that even though there were common bands between the unburned and the severely burned samples, the community structure of the samples from the unburned site grouped separately from those of the severely burned sites collected 2, 13, and 25 months post-fire. Generally, the microbial community composition in the unburned samples did not change significantly over two years. These data support the hypothesis that the soil microbial community was selected by both the direct and indirect effects associated with the wildfire in the initial two years after the perturbation. Rather than return to the predisturbance state, the soil microbial communities may reflect an alternate state two years following the fire.

Effects of urban land-uses have long term implications for the structure and function of natural ecosystems that may extend far beyond the land-use itself. Specifically, natural disturbance and succession in forest ecosystems have been highly altered by human-caused land-use and fire frequency changes. Changes to forest community structure and composition can affect the long-term sustainability of areas such as the New Jersey Pinelands, a fire-dependent ecosystem. By combining historic maps of fire frequency and land-use change, I assessed the effects of human development patterns on fire and forest composition in the Pinelands. These assessments showed lower fire frequency and higher transitions from pine to oak forest cover in close geographic proximity to altered land. Additionally, I investigated our ability to detect the effects of fire on water quality measures using data from gauged watersheds. No significant effects of fire could be determined due to a lack of water quality data associated with wildfires in space and time. I used a spatially-explicit forest disturbance and succession model to investigate how increasing levels of altered land and changing fire regimes may affect forest composition in the future. Additionally, I added climate change to disturbance and succession modeling to incorporate this additional forcing on fire and forest composition. These scenarios showed an overwhelming trend toward oak dominated forest within 100 years, except in the unique pine plains area, where pine species still dominated. The potential of this type of dramatic shift from pine to oak cover represents a radical departure from current forest composition and needs to be addressed by managers of the Pinelands National Reserve in order to maintain the essential Pinelands landscape. Modeling the potential influences of current and future altered land as well as changes in fire regimes in our study area elucidates the degree to which fire and climate disturbances may alter forest composition.

Wildland fires are occurring more frequently and affecting more of Earth's surface than ever before. These fires affect the properties of soils and the processes by which they form, but the nature of these impacts has not been well understood. Given that healthy soil is necessary to sustain biodiversity, ecosystems and agriculture, the impact of fire on soil is a vital field of research. Fire Effects on Soil Properties brings together current research on the effects of fire on the physical, biological and chemical properties of soil. Written by over 60 international experts in the field, it includes examples from fire-prone areas across the world, dealing with ash, meso and macrofauna, smouldering fires, recurrent fires and management of fire-affected soils. It also describes current best practice methodologies for research and monitoring of fire effects and new methodologies for future research. This is the first time information on this topic has been presented in a single volume and the book will be an important reference for students, practitioners, managers and academics interested in the effects of fire on ecosystems, including soil scientists, geologists, forestry researchers and environmentalists.

The Normalized Burn Ratio and Composite Burn Index were used to classify burn severity in three sites that experienced lightning-ignited wildfire in the year 2000. The effect of burn severity (unburned, low, moderate, and high severity classes) was investigated on vegetation and soil microbial community composition. Vegetation communities showed a strong response to burn severity, with distinct communities associated with each burn severity class. Indicator Species Analysis was used to identify plant species associated with each burn severity class; one interesting result from ISA was that trembling aspen (Populus tremuloides) seedlings emerged as an indicator of the moderate severity class. Species richness and tree seedling density differed among burn severity classes. Soil microbial communities were analyzed using Phospholipid Fatty Acid analysis and showed moderate variation among burn severity classes and study sites. Total soil carbon and nitrogen did not differ with burn severity. The C:N ratio, total soil S, and soil pH differed significantly among burn severity classes. While the effect of burn severity is pronounced upon vegetation three years post-fire, effects on soil microbial communities are less evident. This could be attributed to the insulating properties of soils, the time elapsed after fire, or it could be an artifact of the sampling technique.