Simulation of Episodic Winter Warming on Dehardening of Boreal Forest Seedlings in Northern Forest Nurseries

In recent decades, forest nurseries in eastern Canada have been faced with periods of mild winter weather, delayed snowfall, and low seedling protective snow cover combined rains instead snowfall. These extreme conditions resulted the loss millions seedlings, particular those that overwinter outdoors, probably due to their dehardening. The main objective this study is simulate different warm weather at beginning end evaluate effects on dehardening growth Picea mariana glauca seedlings response freezing temperatures. Three warming treatments were simulated (control, 1 day, 3 days 10 °C) followed by three temperatures (−4, −12, −20 °C). winter, regardless treatment, two species tolerated without any apparent damage. However, absence cover, did not show frost tolerance °C. On other hand, showed normal after undergoing frosts −4 °C −12 °C, similar observed for control seedlings. Different cultural practices protection strategies are proposed improve reduce