I looked around a bit on the web, for Colorado I found:

"Best Advice: Swedish columnar aspens need moderate to high soil moisture and are more disease resistant and long-lived than Lombardy poplars. They are excellent for screens, hedges, shelterbelts, or as an accent tree. Because of the narrow growth habit these trees are also good for small yards.

So I'd guess the problem would be dry soil in the winter - which could be handled with a good mulch and an occasional watering.

Thats a nice looking tree. I'll be on the lookout for one to try here.

Here is a link that might be useful: link

I have a few swedish columnar aspen. I'm at about 6,000 feet. They were about 10-12' tall when I bought them 14 months ago. They are now at about 18'. I planted them properly and water when necessary. I would buy them again without hesitation. I bought them for disease resistance, insect resistance and reduced suckering in a columnar tree. They also held up well under the heavy snow we had a few weeks back when they still had their leaves.

Here is one at the Cheyenne Botanic Garden, elev. approx. 6000ft