Tree of Heaven (also known as Chinese sumac) is a small deciduous tree species (to 20 m tall) in the Simaroubaceae that originates from China. It was introduced to North America as an ornamental species, and is now found across most of the US (exclusive of the north-central states); in Canada it is found in Ontario, Quebec and British Columbia (USDA 2010). In British Columbia, it is reported from southeastern Vancouver Island, the Fraser Valley and the Okanagan. Wikipedia (2010) provides the following historical note for this species: "The tree was first brought from China to Europe in the 1740s and to the United States in 1784. It was one of the first trees brought west during a time when chinoiserie was dominating European arts, and was initially hailed as a beautiful garden specimen. However, enthusiasm soon waned after gardeners became familiar with its suckering habits and its foul smelling odour. Despite this, it was used extensively as a street tree during much of the 19th century."
Tree of Heaven has distinctive large, pinnately compound leaves (1-4 feet in length), each with 10-25 leaflets. Bark is smooth with prominent lenticels. This is a summer-flowering species (June) that produces small green flowers borne on large terminal panicles. It produces pods (samaras) that are often spirally twisted; seeds are wind-dispersed. Plants will grow under a variety of conditions, and are tolerant of nutrient-poor soils such as clay (Global Invasive Species Database 2010). It is a rapidly growing, invasive species that reproduces both sexually by seed, and asexually by suckers. It produces large quantities of seed--each tree can produce up to 325,000 seeds per year (NatureServe 2010). It sprouts readily from cut stumps and root fragments (Global Invasive Species Database 2010). In our region, it resembles Japanese walnut (Juglans ailanthifolia)--an introduced species in BC--and staghorn sumac (Rhus typhina)--a garden species. Leaves produce an unpleasant odour when crushed, while staghorn sumac leaves are odourless. Tree of heaven is also easily distinguished by the presence of 1-3 coarse teeth at the base of each leaflet, and a noticeable gland on the underside of each tooth (Hitchcock and Cronquist 1973). Widely plant in urban areas, pollution tolerant (NatureServe 2010).
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