The Shapes Of Trees: Ailanthus


Ailanthus in winter (photo by Kate St. John)

The Shapes of Trees continues today with an Asian import.

Some Pittsburghers call this tree a sumac but it’s a case of mistaken identity. Sumacs are in the genus Rhus. This tree is an Ailanthus, specifically Ailanthus altissima. Its common names include Tree-of-Heaven as it is called in China, and “Tree From Hell” because it’s so invasive in North America.

Ailanthus has a unique shape in winter with sparse, thick, crooked branches in an open crown. They’re always reaching up.

The branches look crooked from a distance because the twigs are stout and blunt and the buds are large and alternate. Each bud changes the angle of the twig. A twig can be as fat as your finger.

Ailanthus altissima twig (photo by Kate St. John)

Ailanthus grows easily in waste places. David Sibley writes in his Guide to Trees,

Trees have been known to sprout from roots 150 feet away from the original trunk and grow over 12 feet in a year.

The Sibley Guide to Trees, page 353

Read more in this vintage post, Winter Trees: Ailanthus.

(photos by Kate St. John)