Invasive Species -


Tree-of-heaven / Copal Tree
(Ailanthus altissima (Miller) Swingle )


Photos & Description courtesy of IPANE

Where it's from



What Tree-of-heaven / Copal Tree does to the habitat

Sending up many root sprouts, Ailanthus quickly becomes a thick colony. It practices chemical warfare as the leaf litter and the roots exude substances that prevent the growth of other plants.

Sewer piper and foundations are prey to its aggressive root system.

Note: It gained its name as tree of heaven being observed to grow directly out of rock. It is the tree that grows in Brooklyn, a symbol of achievement overcoming hard circumstances.



CAUTION: the sap Ailanthus contains quassinoids, chemical that can cause debilitating headaches, nausea and heart problems if you do not protect yourself from exposure to it while handling and cutting.

You can pull up small tree by hand. A little larger, you might want to try a weed wrench ( that gives you a mechanical assist. Dispose of them. Trunks left on the ground can sprout new trees.
Just cutting the trees will only multiply the number of new shoots sent up. So cutting must be combined with herbicide application.


For larger trees, try cutting a wedge in the trunk and spray with herbicide. If you want to spray the foliage, do it in the summer.


Common Name

Full Scientific Name

Copal Tree

Ailanthus altissima (Miller) Swingle

Family Name Common

Family Scientific Name

Quassia family Ailanthus altissima


Botanical Glossary

Ailanthus altissima is a rapidly growing dioecious tree that can reach over 18.3 m (60 ft.) in height. The leaves are 0.3-0.9 m (1-3 ft.) long . Each leaf is comprised of 11-25 ovate-lanceolate leaflets which are each 7.6-12.7 cm (3-5 in.) long. They are truncate at the base and acute or acuminate at the apex. There are usually one or more coarse teeth at the base of the leaflet, and each of these teeth has a large gland beneath it. The bark of this tree is extremely smooth and pale gray in color. The inflorescence is pyramidal in shape and is 10.0-20.3 cm (4-8 in.) long with greenish to greenish-yellow flowers [5 mm (0.2 in.)] that appear in late spring. The staminate flowers and broken twigs have an unpleasant scent. The fruits are twisted samaras that appear from September to October on the female trees. They are yellow-green to orange-red and changing to brown in the winter, and are 5 cm (2 in.) long. Page References Bailey 611, Fernald 953, Gleason & Cronquist 355, Holmgren 335, Magee & Ahles 697.

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