Old World aspen with a broad much-branched crown; northwestern Europe and Siberia to North Africa WordNet 3.0 & Open English WordNet

Populus tremula is a species of poplar native to cool temperate regions of Europe and Asia, from Iceland and the British Isles east to Kamchatka, north to inside the Arctic Circle in Scandinavia and northern Russia, and south to central Spain, Turkey, the Tian Shan, North Korea, and northern Japan. Wikipedia

Populus tremuloides, the American aspen, the leaves of which have flattened petioles that cause them to tremble in the breeze. Wiktionary