Maximizing white spruce (Picea Glauca) productivity in a drying climate through tree improvement
University of New Brunswick
Improving forest productivity is critical to meet increasing global demand for wood products. However, increased frequency of drought events can negatively impact tree growth and productivity. I investigated volume growth genetic variation and drought response of three 20-year-old white spruce (Picea glauca) varietal test sites in New Brunswick, Canada with the objective to: 1) test if volume breeding values could be used to predict drought vulnerability through tree-ring analysis of a recent multiyear drought; and 2) to quantify the within and among family variation for volume growth to determine the optimal ratio of varieties to families that need to be field tested to maximize genetic gains for growth traits. I found varieties with higher genetic volume growth rates exhibited higher drought resistance, suggesting that breeding for volume growth could also improve drought resistance. Also, there was more within family variation than among family variation, suggesting that more varieties per family and fewer families should be bred and tested to maximizing genetic volume gains.