Impact of Fire on the Geology of Soils

Fires are an important and healthy process in many ecosystems. The lack of fires can cause new plant communities to invade an area . The regular occurrence of fires can keep one plant community dominate, like oak savannas. Fires can leave burnt sticks the size of trees and clumps of charcoal where bunch grass use to grow, but not for long. An area that was burned will re-grow, grasslands will be green the next growing season and forests will typically show new growth soon after. Somewhere in the process of a fire the soil it travels over is effected. Alterations happen immediately after a fire passes over a soil and can continue years after a fire has gone. Soils are impacted in two main ways; by the entering of nutrients form the brunt organic matter (living vegetation and by the litter on the surface of the soil) and the heating of the soil and the nutrients already present in the soil. The greater the duration and intensity of the fire will influence the amount of alteration of the soil.

A prescribed burn is usually less intense than a wildfire. Prescribed burns are put on when conditions are right, meaning that the area is not too dry or too large. Wildfires on the other hand can start at any time and burn vast areas and last for days out of control. One reason wildfires usually are more intense than prescribed burns is because of the fire suppression that lasted most of this century allowed large amounts of fuel to pile up waiting to be burned. Vegetation in these areas will grow back regardless, but it is the soils that have a harder time recovering from the intense heat. One other difference to consider when looking at the types of fires, is a forest fire verses a grassland fire. Forest fires usually last longer and h...

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