Will Douglas Fir grow well in Edmonton? - yes, there are nice 50+ year old specimens in the City. For whatever reason though, it is rarely planted.

Will Doug Fir naturalize in the Edmonton area? - maybe...depends on the original seed provenance versus climate, competition from other plants, etc. I live in eastern Ontario and Doug Fir grows quite well here. That said, I've only seen one location where it ever self seeded into a natural area.

Details on the seed source of your trees? - unknown but interior Doug Fir seems to occur all over...from Banff & Jasper all the way to the coast though it isn't dominate in all climate zones.

Here is a link that might be useful:

Also...good luck with your White Fir.

Here is a link that might be useful:

I know they grow in captivity. I also know that you have to pick your seed source carefully. It's normal habitat is generally warmer than we are here.

I'm trying to understand what controls it's successful adaptation. I suspect that understanding why it only grows in half the subzones of SBS is part of the answer.

Concolor: I've got one in my front yard, now almost 6 feet high. Concolor tend to have problems with buds drying out in constant winter wind. I've had problems with them and winter bud desication. Hence my thoughts that seed sourced from a high interior desert mountain range might do well. The San Juan forest has longer winters than we do, although not quite as cold.

Douglas Fir is growing in Russia in zone 3. I guess it is Pseudotsuga glauca.

I talked to a guy who worked in BC forests since posting this. The original survey didn't know about temperature. Basically they did sample surveys across the province and assigned both the temperature and warmth subzones on the basis of what they saw growing. They would assume generally that higher elevations meant colder. Windward faces meant wetter, northern faces later springs, shorter growing seasons.

So my cart is in front of the horse. The reason that there is no DF in the other zones is that DF was used to define the subzone. Later analysis of records pinned down the climate more precisely. But the small difference between where DF grows and wehre it doesn't speaks to it being some other factor.

He speculated that it may be the provenance of late frosts. Fir buds just after bud break are susceptible to frost damage. It becomes a race condition: Can the tree get tall enough to escape late frost before there is a bad year.

This fits in with an article I saw about bud break in A. lasiocarpa (Alpine fir) that bud break tends to be earlier, referenced to average temps, in northern latitudes. Daylength increases more rapidly in the north, so the risk of a late frost is somewhat lower. Moreover, the growing season in the north is shorter. The combination favours trees that 'jump the gun' even at the risk of higher seedling mortality.