Utah State University Extension
Aspens are one of the more popular forest trees in the Intermountain West. They add a brilliant yellow glow to the collage of fall colors. In an attempt to enjoy these beautiful trees around the home environment, many well-intentioned homeowners purchase or otherwise acquire aspens and transplant them into their landscapes. Unfortunately, aspens are not adapted to the environmental conditions of the valleys, and many problems develop.
Baker, Fred A.; Alston, Diane G.; and Nischwitz, Claudia, "Aspen, Important Pests of Ornamental Spen" (2012). All Current Publications. Paper 848.