Abies lasiocarpa

Corkbark fir is an extremely southern variant of the subalpine fir (A. lasiocarpa), in fact it was earlier held to be a separate species. It is most easily distinguished by pale grey, almost cream-coloured, soft, corky bark. The needles are dense and a beautiful blue-grey, like those of the southern mountain forms of the subalpine fir.

Corkbark fir grows naturally in Arizona’s San Francisco Mountains, far to the south, but at such high elevations that it is hardy in Finnish winters, at least at Mustila. So far it has hardly been tried elsewhere in Finland. The species was first planted at Mustila in 1907 as one of the basic elements of the Rhododendron Valley. The trees, with their dense, silvery needles, gave the area a gleaming soft aspect until their lower branches slowly deteriorated due to aphids; rot, storm and snow-damage added to the problems. Although corkbark fir isn’t a long-lived species at Mustila, it has its own particular decorative value and should be retained as one of the Arboretum’s features through constant renewal.

The Subalpine fir, generally blue-grey in colour, is native to North America. It is closely related to the more eastern Balsam fir (Abies balsamea), but they each have adapted to their individual range, the Subalpine fir to the western mountainous areas of North America.

Being a continental mountain species, Supalpine fir is liable to damage by spring frosts but is otherwise hardy to severe winter conditions. Provenance greatly affects its success in different parts of Finland. At its best, Subalpine fir is an excellent landscape tree, useful also to florists for its foliage, not to mention its use as a Christmas tree. It is, however, rather short-lived for a conifer – at Mustila, for example, all the 80-year-old Subalpine firs suffer from butt rot.

The outward appearance of the species displays great intra-specific variation, generally the more southerly stands have more bright bluish or silvery grey needles. The Arizona provenances have been named corkbark fir (Abies lasiocarpa var. arizonica).