Species, tree size, and overstory environment affect likelihood of ice storm damage to understory trees in a mature Douglas-fir forest

Abstract

Abstract Glaze events (i.e., ice storms) are a potential source of disturbance whose effects have not been heavily researched in forests in the Pacific Northwest. This study examines the effects of species, size, and overstory environment on occurrence, source, and severity of damage sustained by planted understory trees in a mature Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco) forest as a result of the glaze event that struck the central Oregon Coast Range in November 2014. Understory tree species were Douglas-fir, grand fir ( Abies grandis (Douglas ex D. Don) Lindl.), western hemlock ( Tsuga heterophylla (Raf.) Sarg.), and western redcedar ( Thuja plicata Donn ex D. Don). Overall, western redcedar was damaged least frequently, and western hemlock was damaged most frequently. Redcedar was less susceptible to crown damage and more susceptible to bending damage than the other three species, while hemlock showed the opposite trend. We found significantly lower (P