First-year survival and growth of bareroot, container, and direct-seeded Nuttall oak planted on flood-prone agricultural fields

摘要

Container and 1-0 bare root Nuttall oak ( Quercus nuttallii, Palmer) seedlings were hand-planted, and acorns were direct- seeded, in a Sharkey soil (very fine, montmorillonitic, nonacid, thermic, Vertie Haplaquepts). The seedlings and seed were planted in January, February, March, and June, 1993. Flooding, to a depth of 2 meters, occurred on the study site from late March to late May. Seedlings planted in June were not flooded. Regardless of planting date, mean first-year survival for container seedlings was greater than 80 percent. Overall mean survival for bareroot seedlings was about 40 percent and direct-seeding survival was 30 percent. Bareroot seedling survival was about 60 percent when seedlings were planted in January or February, but fell below 25 percent when seedlings were planted in March and June. The reduction in bareroot survival was attributed to long-term cold storage. Mean first-year total height of container, bareroot, and directseeded seedlings was 46 centimeters, 34 centimeters, and 15 centimeters, respectively. However, stem dieback resulted in shorter seedlings after the first year in the field. Container seedlings were slightly shorter than when planted, but bareroot seedlings averaged 22 centimeters shorter. Greater survival and flexibility with regard to planting schedules may justify the use of container seedlings on flood-prone sites.