Trembling Aspen Stands as Firebreaks: What Options Are Available For Stimulating Aspen Stand Expansion (06/29/18) June 29, 2018 by WFCA Office Trembling aspen (Populus tremuloides Michx.) is the most widely distributed tree species in North America. Aspen forests are important for wildlife, livestock, water quality and quantity, timber resources, and recreation. Read the full article here. Share this page