Ailanthus altissima. TREE OF HEAVEN. China
SIMAROUBACEAE (Quassia family)

A nice shady tree, tree of heaven has a flair for escaping from cultivation and is doing well along Junipero Serra Boulevard at the Golf Course. Bunches of red samaras color the trees late in summer. The trees also grow wild along hot roadsides in the foothills of the Sierra Nevada and are famous for being able to grow out of concrete in Brooklyn. Such indomitable suckering may of course not be welcome. This botanical marvel is now the subject of breeding experiments to develop tougher wood and fewer flowers to fit it for street tree planting in situations where few choices are open. Some cities with extreme climates and dense automobile pollution are heavily dependent on just a few species, e.g. the London plane and honey locust in New York, with the risk that one disease could wipe out nearly half the trees planted over several decades. “It will grow where all else fails, and it’s better to have an Ailanthus than nothing” (Dr. Howard S. Irwin, Executive Director of the New York Botanical Garden). As of 1972, it was illegal to plant the tree of heaven along New York city streets.

The tree of heaven is not planted by design at Stanford but volunteers freely. The leaves have a distinctive odor and trees bearing staminate flowers have a smell that is objectionable to some. For this reason, female trees are preferred for planting in those areas where the tree of heaven is cultivated.

Three females and a male are opposite 267 Santa Teresa Lane. A large multitrunked specimen is at Phi Sig house, 1018 Campus Drive East. Another giant is at the southeast corner of the Kingscote Gardens building. A group is on the north side of Applied Physics/Ginzton Lab, behind some Chinese pistache trees.

Illustrations (links open new windows): habit | fruit 9/23/06

Additions/Revisions: Dioecious tree: pistillate and staminate flowers are on separate plants as noted above.

Name derivation, genus | species Latinized version of the native Moluccan word ailanto (sky tree) for a species of this genus | tallest

Related material: Canopy Trees for Palo Alto Tree Library

Botanical name index | Common name index | Family home