Wildfires in the western United States are concerning in part because conifer forests may not regenerate under increasingly warm, dry climate conditions and severe burning. This study compared the relative importance of differences in fire-caused tree mortality, which limits seeds available for tree regeneration, to the impacts of warm, dry climate conditions in determining postfire conifer regeneration. Using observations from over 10,000 sites, we found that warmer, drier conditions are leading to less tree regeneration after wildfires. We also found evidence that management interventions that reduce wildfire severity can partially offset these climate-related declines in tree regeneration. Our work highlights the next few decades as a window of opportunity over which management could minimize the likelihood of fire-caused forest loss.