Effects of lift date and seed lot on field performance of containerized Douglas-fir seedlings

To determine the effect of nursery lifting dates on field performance of containerized Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) seedlings, we lifted and stored seedlings from 2 seed lots on 9 dates from late October 2019 to early March 2020. We planted the seedlings in a field test and in large pots in April 2020. All seedlings broke bud and grew vigorously. No mortality occurred in the pots, and less than 6 percent mortality occurred in the field test. Bud burst was slightly faster for seedlings lifted after mid-January than for those lifted on earlier dates. We found consistent differences in phenology and growth between seed lots, representing seeds collected from the same seed orchard at different years. Seed lot effects were confounded, however, by differences of sowing time and dormancy induction and must be studied further.