Nitrogen (N) is one of the primary limiting nutrients in all ecosystems. Therefore, it is important that we develop a thorough understanding of N cycling processes in forest ecosystems to minimize N losses to fire, harvesting, and other forms of land management. The influence of fire on N fixation has not been studied in any detail, furthermore the influence of fire exclusion and fire as a restoration treatment are poorly understood. Forest managers in western Montana have practiced active fire suppression for over 100 years. Previous studies have shown this activity to inhibit recolonization of sites by N fixing plant species. This may make free-living heterotrophic N fixing bacteria an important source for N recovery in ponderosa pine ecosystems following disturbance. We investigated the presence and activity of free-living N fixing bacteria that colonize decaying roots following fire. Studies were conducted to determine the effect of fire or the time since last fire on N fixation rates in decaying roots. N fixation rates were estimated using acetylene reduction and individual organisms were isolated on N free media. The effect of fire on the presence and activity of N fixing bacteria in the roots of dead plants will be discussed.