Conservation New England: Ailanthus altissima is native to Asia, and began its journey west by being introduced to Europe in 1751 by a French Jesuit preist who brought it from Nanking, China to England. The first known specimen was brought into the United States a few decades later by William Hamilton, who planted this species in Philadelphia (Shah 1997). People admired the beautiful foliage of these fast-growing trees, and for over a century have been planting it as an ornamental ...

[USDA FEIS] Introduction to California: Tree-of-heaven spread in North America apparently followed 3 introductions from China. It was 1st imported to Pennsylvania in 1784 as an ornamental. A 2nd introduction occurred in New York in 1820, where tree-of-heaven was again planted as an ornamental. Both eastern introductions were from English stock imported from China. Tree-of-heaven was commercially available in eastern nurseries by 1840. The 3rd introduction was in California during the Gold Rush of the mid-1800s. Chinese immigrating to work in the gold fields and in construction of the transcontinental railroad brought tree-of-heaven to California, probably because of the tree's medicinal and cultural importance in their homeland. (link added by Jessica Johnston)