In forested ecosystems of the western U.S. the timing and growth of conifer regeneration following wildfire is a critical component of tracking and predicting future ecosystem trajectories. For both managers and researchers determining the age, and therefore establishment date, of tree seedlings after fire offers important insight into the resilience of an ecosystem. The terminal bud scar count method is a non-destructive seedling aging method that can be easily implemented in the field; however, factors such as seedling species and age have been shown to negatively impact the accuracy of aging with this method. Three widespread western U.S. conifer species (black spruce [Picea mariana], ponderosa pine [Pinus ponderosa], and grand fir [Abies grandis]) will be evaluated for accuracy and magnitude of error associated with aging by terminal bud scar counts as compared to aging by growth ring counts. These results will give both managers and researchers more confidence in the inferences they can make with seedling age data and will be provided to managers in Alaska and the Northern Rockies via an in-person workshop in the Malheur National Forest (where one of our sample sites is located), via a webinar on one or both applicable Fire Science Networks, and via a field guide publication containing accuracy estimates as well as guidelines for accurately using the terminal bud scar count method. Additionally a methods paper will be published in a refereed journal. The research proposed in this grant would leverage current funding for my dissertation work (JFSP grant 14-1-02) by expanding my dissertation to provide in-depth validation of methodology used to age black spruce, ponderosa pine, and grand fir seedlings as well as produce a direct product for managers in the region.