Plantation white spruce mortality: estimates based on aerial photography and analysis using a life-table format

White spruce, Piceaglauca (Moench) Voss, mortality was estimated in two 142-ha, 11- and 12-year-old plantations in north central Minnesota, using small-format color aerial photography at a scale of 1:9600 and groundplots. A double sample with regression sampling method determined mortality of trees 5 years after planting to be 3.9 ± 0.33%. Life-table analysis showed 20.7% loss during the first age interval, 0–4 years after planting. The yellow-headed spruce sawfly, Pikonemaalaskensis (Rohwer), was responsible for 65% of the mortality in the last two age intervals. Differential mortality and growth of white spruce was observed between plantations. Site preparation is suggested as a possible cause of these differences.