Apparently there are quite a few in the Portland area. Someone has been mapping them.
https://www.google.com/maps/d/viewer?mid=142zMsWAyuf9uYKGu7t...
https://www.google.com/maps/d/viewer?mid=142zMsWAyuf9uYKGu7t...
The trees have sexes, so one has to find the female trees.
There are quite a few in Portland, and all relatively the same age because they were given away at the lewis and Clark exposition of 1905 by a representative from Chile.
https://slabtowntours.com/2016/04/19/fun-fact-26-the-seedlin...