Changes in wildfire activity in the western U.S. threaten the capacity for forests in the region to recover after wildfire. This threat is partially due to the fact that wildfires reduce the amount of nitrogen, a critical nutrient for plants, that is stored in the forest. Here, we studied the importance of soil as both a reservoir and source of nitrogen to western forests recovering from severe wildfires. Additionally, we measured rates of nitrogen fixation, the process that converts atmospheric nitrogen into plant-available forms, in the soil at depths that have not yet been measured. Ultimately, we find that soils act as large nitrogen reservoirs that are resilient to changes in wildfire activity.