Along with color change, structure is also altered and most always associated with areas that underwent color change, probably due to the fact that those areas had the most heating from the fire. As clay minerals and other phyllosilicates are heated, they are broken down. The breakdown of the small particle size in the soil alters the soil directly by the reduction of small sized particles in the structure of the soil. The increased size of the soil particles causes the soil to be less stable. The larger size allows the soil greater permeability.
Negative implications can result as the form of landslides or slumping.
The increased erosion is a result of the larger particles having less an ability than clay particles to hold together the soil. The next property of a soil that can be effected by fires is a soil's ability to hold or repel water. A fire can create a hydrophobic layer in the effected soil. The layer can be of varying thickness and intensity. The alteration of structure by heating can result in a coarser texture, which can amplify the hydrophobic layer, which otherwise would not have been as large.