Post-fire soil ecology: Properties and erosion dynamics

Many physical, chemical, mineralogical, and biological soil properties can be affected by wildfires. The effects are chiefly a result of fire severity and environmental factors; therefore, the consequences are diverse. Severe fires generally have several negative effects on soils, including significant removal of organic matter, deterioration of both structure and porosity, considerable loss of nutrients, and increased runoff and erosion. The effects of fire on most soil processes have been clearly demonstrated at the plot scale, yet it has been difficult to quantify their importance on larger scales. Considering fire severity and the threshold temperature at which the different soil properties change, wildfires may affect chemical characteristics and reactions within the soil. The rate of recovery may last a couple of decades, during which time many nutrients are mineralized and exposed to increased erosion. Nutrients from the ash enhance microbial growth and boost fungal activity, affecting other soil physical properties. In summary, the magnitude, rate, and type of most fire-affected processes are determined by the complex interactions between the physical, chemical, and biological properties of the soil as well as the characteristics of the fire itself. This paper provides an integrative overview of fire effects on soil properties and dynamics.