Survival and growth of eastern larch, balsam fir, and black spruce six years after winter browning in northeastern Ontario, Canada

Abstract

In spring 2007, young conifers suffered extensive needle and bud injury near Hearst, Kapuskasing, and Cochrane in northeastern Ontario, Canada. Analysis of weather data revealed that the damage was likely caused by earlier than normal loss of cold hardiness during higher than normal temperatures in late April and early May. The dehardened trees were damaged in the cold days that followed. We report the survival and growth of eastern larch (Larix laricina), balsam fir (Abies balsamea), and black spruce (Picea mariana) in the affected area based on field assessments and stem analysis of affected trees following the event. Total survival through six growing seasons following damage was 98% in eastern larch but only about 70% in balsam fir and black spruce. The effect of the damage on tree growth was greater and longer lasting for diameter than height. Both survival and growth reductions were associated with high levels of mature needle loss and bud damage. Implications of these findings for forest management are discussed in light of expected climate change.