White spruce (Picea glauca [Moench] Voss) seedlings were operationally outplanted in May 1993 on a boreal mixedwood site in Biggs Township, Ontario. A factorial randomized block design with four replications accommodated three main treatments for establishing white spruce: namely, corridoring, mounding, and pelleted hexazinone. Plots (50 ×100 m) were split longitudinally between bareroot and containerized stock types. Immediately after planting and at the end of the first 3 growing seasons, 2 400 trees (100 in each half of each split plot) were assessed for performance.
Since establishment, photosynthetically active radiation (PAR) was determined 14 times at 1 m above ground level at 360 outplant locations (60 per half split plot) in Block I, and 9 times at leader-tip level of surviving outplants at those locations. Significantly lower (P <0.01) survival rates for bareroot stock than for containerized stock in both the hexazinone and corridor treatments are attributed to low vigor of the bareroot stock; the virtual absence of first-year mortality among containerized stock in each of the main treatments shows that outplants were not endangered by pelleted hexazinone used as described. Through 3 growing seasons, mounding gave the highest survival. The effectiveness of the hexazinone treatment may have been diminished by excessive soil moisture and insufficient herbicide dosage. The height increment of containerized stock was significantly greater (P <0.01) than that of bareroot stock in 1994, and significantly smaller (P <0.01) in 1995. PAR values were generally lowest in the hexazinone treatment and highest in the mounding treatment, but differences in PAR between the hexazinone and corridoring treatments decreased markedly during the third growing season.