Effects of early spring photosynthesis on carbohydrate content, bud flushing and root and shoot growth of Picea glauca bareroot seedlings

The effects of early spring photosynthesis were studied in white spruce [Picea glauca (Moench) Voss] bareroot seedlings. Before spring lifting, one group of seedlings was covered in nursery beds from March 25 to April 18, 1994. The second group, used as control, was left uncovered. The third experimental group consisted of fall-lifted seedlings that were removed from frozen storage on March 25. 1994 and placed in nursery beds. The fourth group were fall-lifted seedlings that remained in frozen storage. On April 18, 1994, uncovered seedlings had higher levels of nonstructural carbohydrates in needles and roots compared with covered seedlings. Fall-lifted seedlings placed outside in spring also had higher total nonstructural carbohydrates in needles and roots compared with seedlings that remained in frozen storage. Covered and uncovered seedlings had similar root growth potentials before planting. However, when planted in the forest, uncovered seedlings showed higher root growth rates and terminal shoot growth in the second year following planting compared with covered seedlings.