Soil aggregate degradation by medium and high intensity fires is often attributed to loss of soil organic matter, whereas low intensity fires are often considered benign to soil aggregate degradation because organic and inorganic binding agents are relatively stable at these low temperature burns. Because of this, there are limited studies specifically focusing on the effect of low intensity fires on soil aggregation. However, recent long-term studies have reviewed that aggregate breakdown can occur long periods of time after low intensity burns. The aggregate breakdown could not be explained by loss of soil binding agents. Previous studies have indirectly tested the hypothesis that stress exerted by rapid vaporization of soil pore water during low intensity burns could lead to aggregate breakdown in the long term. I further explore this mechanism of soil aggregate degradation in a forest sandy loam and shrubland loam soil. In this work, I (1) provide direct proof of the hypothesis by measuring the pressure inside individual moist soil aggregates burned at 175°C and (2) show that soil aggregate degradation by this mechanism can expose physically protected soil organic carbon to decomposition. The pore pressure increase in both the forest and the shrubland aggregates increased with increasing soil water content. Furthermore, tensile strength of both types of soil aggregates decreased with increase in soil water content, suggesting that moist soil aggregates may be more susceptible to breakdown by this mechanism. Additionally, I provide a model predicting that strain on aggregates from rapidly vaporized soil water is maximized in initially wetter soil aggregates. The degradation of soil aggregates by rapidly vaporized soil pore water was observed in forest soils that experienced increase in rate of decomposition of soil organic following low intensity fires. Increase in decomposition of soil organic carbon in shrubland soil aggregates were observed for all burn treatments, and was linked to increase in dissolved organic carbon likely due to loss of cytoplasmic organic compounds from lysis of soil microbes. The results provided in this thesis suggest that low intensity burns can negatively affect soil aggregation in ways that were not studied before since low intensity burns are often considered benign to soil aggregation, and that more research should focus on low intensity fires’ effects on soil aggregates as the number of these burns have been increasing over the last few decades.