associated with pine and juniper, which are thought to cause respiratory system ailments in some animals. Heat-treated aspen is a popular material for the interiors of saunas. While standing trees sometimes tend to rot from the heart outward, the dry timber weathers very well, becoming silvery-grey and resistant to rotting and warping, and has traditionally been used for rural construction in the northwestern regions of Russia (especially for roofing, in the form of thin slats). References Further reading Fox, Mark, Linda E. Tackaberry, Pascal Drouin, Yves Bergeron, Robert L. Bradley, Hughes B. Massicotte, and Han Chen (2013). "Microbial community structure of soils under four productivity classes of aspen forests in Northern British Columbia". Ecoscience 20(3):264–275. . External links Aspen Information Resource, U.K. Quaking Aspen Forests of the Colorado Plateau Bioimages: Populus grandidentata bigtooth aspen Aspen Research Bibliography Aspen Photo Gallery Aspen Compounds, Medicinal Benefits and Uses Loyola Medicine: Aspen Dosage, Interaction, Warnings and Side Effects Steens Aspen Video produced by Oregon Field Guide Medicinal plants Negligibly senescent organisms Plant common names Populus