Observations were made on the growth of white spruce (Piceaglauca (Moench) Voss) and Engelmann spruce (P. engelmanni Parry), each planted at a single location in the interior of British Columbia. In both species bareroot stock (either 2 + 0 seedlings or 2 + 1 transplants) with a low root growth capacity made only limited height growth during the first two seasons after planting. In the first season, many short stem units were formed, whereas in the second season, stem units were much longer but many fewer. The length of needles formed after planting by the bareroot trees was, in the first season, only about half that of needles formed the previous year in the nursery. Needle length increased slightly in the 2nd year. Container-grown trees (1 + 0 seedlings from 336-mL containers), which had a high root growth capacity, made relatively good height growth in the first season when they formed long needles and stem units. Height growth by these seedlings was much less in the second season, however, as were needle length and stem unit number, but not stem unit length. Application of slow release N,P, and K fertilizer at planting improved shoot growth by bareroot trees more in the second season than the first. In contrast, the container-grown stock made a large shoot growth response to fertilization in both the first and the second seasons. The results are consistent with the hypothesis that, as root establishment proceeds, shoot growth tends to be limited by the supply, first of water, then of mineral nutrients. This implies that the early growth of planted spruce can be maximized by using stock with a high root growth capacity, or other adaptations to drought, and applying slow release fertilizer at planting. Observations on the white spruce revealed an acceleration in shoot growth by both stock types during the third season. This followed the establishment, by the end of the second season, of root systems several metres in diameter. A large difference in height: diameter ratio, observed at the time of planting, between the container-grown and bareroot white spruce disappeared entirely in the course of the first three growing seasons.

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Root growth potential (RGP) and needle conductance to water vapour (Gn) of container-grown interior spruce (Piceaglauca–(Moench) Voss Piceaengelmannii Parry complex) seedlings that had been subjected to mechanical (dropping), low-temperature (−15 °C), or heat (35 °C) stresses were determined prior to planting on two forest sites. Field performance measured as survival, height, stem diameter, stem volume, and mean stem volume relative growth rate (RGR) was assessed for each of the 4 years following planting. RGP, Gn, and field performance did not differ between mechanically stressed and nonstressed seedlings. Low temperature and heat stresses reduced RGP, Gn, and field performance of some batches of seedlings, indicating that stock lots with different nursery cultural history had substantially different stress resistance. RGP and Gn were correlated with field performance such that for RGP greater than five new roots per seedling, high (>80%) survival and to a lesser extent greater growth occurred, whereas for RGP less than five new roots per seedling, survival and growth were unpredictable. High survival and better growth occurred for stock lots having Gn > 50 mmol•m−2•s−1, while for Gn < 50 mmol•m−2•s−1, survival decreased. Preplanting stress effects on growth were small and due to RGR reductions in the first field season, which are projected to result in a time delay of 1 year or less in trees reaching a height of 150 cm and a stem diameter of 3.5 cm.

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