As I was walking along the gravel path by the rugby field today, I noticed that we have a tree-of-heaven (Ailanthus altissima) growing on the edge of the canyon. Ailanthus
was considered an exotic Asian beauty when it was first imported to the
U.S. in 1784. These days it’s more commonly considered a nasty,
invasive weed. The tree is extremely hard to kill and it’s got a deep
taproot that makes it hard to dig up. And it spreads like crazy: a
mature, female tree can produce more than 300,000 seeds every year.
Here in southeast Portland we’ve got a moderate tree-of-heaven
infection. There are several large trees in Sellwood and along 28th
avenue, and you can see the young trees popping up in most vacant lots.
But this is the first Ailanthus I’ve seen in the canyon. It’s odd that it hasn’t been more of a problem.
Has anyone seen another tree-of-heaven in the canyon? If so, please
drop me a line. You can see photos and learn more about the plant here:
http://www.nps.gov/plants/alien/fact/aial1.htm
– posted by Niels
