Fire Effects

Fire effects are the physical, chemical, and biological impacts of fire on ecosystem resources and the environment (DeBano et al. 1998). The abiotic effects of fire include its role in changing air quality, water quality, soil properties, and nutrient cycling. Biotic effects include altering vegetation and related impacts on wildlife. Fire effects are the result of an interaction between the heat regime created by fire and ecosystem properties. The particular effect of fire on any one of these components (e.g., the fire severity) is not fixed, but will vary according to site characteristics and fire behavior. For example, the effects of a fire burning under the same conditions may be very different on soils of different textures. Likewise, the effects of fires burning under different fuel and weather conditions can be very different on similar soils.

Knowledge and understanding of fire effects is important for land managers. Fire is a fundamental process of ecosystems that managers are challenged to address in order to meet resource and ecosystem management goals; land managers use fire to achieve beneficial effects and avoid unwanted results. The following sections cover fire effects on air, water, soil, vegetation, and wildlife. For information on how fire affects humans, please see Fire and People.

• Fire Effects on Air Quality: While fire is essential in maintaining many ecosystems, air pollutants emitted from fires can be harmful to human health and welfare. As a result of these risks, increasingly effective smoke management policies and air quality standards are being implemented. This section covers the components of smoke, how smoke affects air quality, how to characterize and predict the amount and movement of emissions from fire, and air quality regulations.
• Fire Effects on Water: Fire can effect water quality both directly, by increasing temperature and nutrients, or indirectly, by increasing sedimentation and turbidity, and altering channel morphology. This section summarizes these physical and chemical effects of fire on water quality and relate how these changes influence the biology of aquatic systems.
• Fire Effects on Soil: Fires affect physical, chemical, and biological soil properties directly by transferring heat into soil and indirectly by changing vegetation and the dynamics of nutrients and organic matter. This section explains the process of heat transfer to soil and summarizes the effects of fire on soil physical, chemical, and biological properties and how these impact surface runoff and soil erosion.
• Fire Effects on Plants: Fires affect plants directly, by injury and mortality, and indirectly, by changing resource availability. These effects translate into vegetation changes at the plant, population, and community level. This section summarizes general adaptations and responses of plants to fire and provides specific examples for many southern plant species. For a discussion of how fire effects vegetation types in the south, please see Fire Ecology.
• Fire Effects on Animals: Fire can affect wildlife directly through injury and mortality, however the most profound effects of fire are caused indirectly by altering wildlife habitat. This section summarizes the general adaptations and responses of birds, mammals, amphibians, reptiles, fish, and insects to fire and provides specific examples for many southern plant species.