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Tree of Heaven
statusTree of heaven (Ailanthus altissima) is a widespread environmental weed but is only listed as noxious in the Southern Tablelands and South East Region in the Queanbeyan LCA, in class 4 (must be controlled in accordance with a local management plan). DescriptionTree of heaven is a fast-growing deciduous tree to 20m high with smooth, grey bark. Large compound leaves are up to 1m long with many leaflets in opposite pairs. There is a gland on a small lobe near the base of each leaflet. Crushed leaves have an unpleasant smell. Small white flowers are carried in terminal clusters, followed by seeds which are red, large and winged. The first four photos are tree of heaven, followed by two photos each of native look-alikes, red cedar and white cedar (see below) and two each of the environmental weeds black locust and honey locust.DispersalOriginally a garden plant, mainly spreading by root suckers. Dumped material may take root. Root fragments can be spread by machinery. Seed must occasionally spread by wind over long distances, despite being quite heavy, as plants are occasionally found remote from towns and gardens.Look-alikesOn the coast there are a couple of native rainforest plants with similar form and large compound leaves. Red cedar (Toona ciliata) has compound leaves with no terminal leaflet, while those of pencil cedar (Polyscias murrayi) do have a single (unpaired) terminal leaflet at the tip of each leaf. Red cedar is deciduous, like tree of heaven, but pencil cedar is not. Neither of these trees has the gland on the leaflet margin which characterises tree of heaven, or the unpleasant smell to the crushed leaf. Pencil cedar holds its leaves more erect than tree of heaven (see photo of young plant). In the harsher tablelands climate tree of heaven leaves tend to be smaller than on the coast, and the tree could perhaps be confused with black locust (Robinia pseudoacacia) or honey locust (Gleditsia triancanthos). Both these trees have furrowed bark, rounded rather than pointed leaflets and thorns (simple on black locust and branched on honey locust) on the stems. Black locust has sprays of attractive cream pea-flowers followed by small thin-textured flat seed pods (see photo) and honey-locust pods are up to 30cm long, and leathery in texture. They both sucker freely, like tree of heaven and are both environmental weeds. The final two photos are of black locust. ControlCut and paint, stem inject, basal bark or spray smaller plants. Plants will sucker from the roots when cut down or poisoned, so repeat treatment is necessary. Do not plough, bulldoze or cut without poisoning, as suckering will be massive.Contact with tree of heaven bark and leaves may cause dermatitis in some people. |
