Douglas-fir (Pseudotsuga menziesii var. menziesii) is an important species in the Pacific Northwest including California forests. Due to the increasing need for reforestation in this region after widespread disturbances related to changes in climate (i.e., drought, megafires, beetle mortality), it is necessary to examine the factors that contribute to performance and survival of planted seedlings in reforestation projects. While most conifer planting in northern California is done in spring, fall planting is also an alternative practice used. With the recent increase in demand of seedlings for reforestation projects beyond which the current infrastructure is capable of, particularly in spring, expanding the fall planting season has potential to mitigate this and constraints to the spring labor force. Here, we studied the first-year performance of both spring and fall planted Douglas-fir seedlings for different seed sources and nursery cultural timings at a single site in northern California. We found that the fall planting can be successful in October or November, while planting earlier requires immediately favorable temperature and soil moisture conditions. Later sowing and blackout regimes also resulted in increases in height growth and bud development while also reducing damage due to spring freezes. For spring planting, early sow and blackout resulted in earlier bud break, while later sow, blackout, and lift dates benefited the first-year growth of height and diameter. Keywords: Douglas-fir reforestation · Dormancy induction · Fall and spring plantings · Nursery practices · Seed source · Seedling cultures
