Characteristics of Subalpine Fir Tree (Abies lasiocarpa) in the Wild

Abies lasiocarpa
Subalpine fir or Rocky Mountain fir (Abies lasiocarpa) is an evergreen tree native to western North America. Its distribution extends from the mountains of the Yukon, British Columbia, and western Alberta in Western Canada, and to southeastern Alaska, Washington, Oregon, Idaho, western Montana, Wyoming, Utah, Colorado, New Mexico, Arizona, northeastern Nevada, and the Trinity Alps of Klamath Mountains in northwestern California.

This tree grows naturally at an altitude of 300-900 m asl in the north of the mountains (rarely to sea level in the far north), and 2,400-3,600 m in the south of the range.

The wood is subalpine fir used for general structural purposes and papermaking. It is also a popular Christmas tree. Subalpine fir is also often grown as an ornamental tree for parks and large gardens, grown for its blue-gray foliage. One of the cultivars is Abies lasiocarpa var. arizonica ‘Compacta’ is suitable for smaller gardens, as it only grows as a shrub up to 4 meters high and 1.5 meters wide. In the UK this cultivar has been awarded the Royal Horticultural Society’s Award of Garden Merit.

 

Characteristics of Subalpine Fir Leaf

Abies lasiocarpa Leaf
Source: inaturalist.org/geographerdave

The leaves are flat and needle-like, 1.5-3 cm long, grayish-green above with broad stomata line, and two blue-white stomatal bands below, also reddish leaf scars. They are arranged spirally on the shoots, but with the bases of the leaves twisted arranged to the sides and above the shoots, with little or nothing below the shoots.

 

Characteristics of Subalpine Fir Fruit

Abies lasiocarpa Fruit
Source: inaturalist.org/mtjones

The cones are erect, 6-12 cm long, blackish-purple with fine yellow-brown pubescence, when ripe they are brown and disintegrate to release seeds in early autumn.

 

Characteristics of Subalpine Fir Tree

Abies lasiocarpa Tree
Source: inaturalist.org/jasonheadley

Subalpine fir grows as a large tree with a height of 20 meters, very high up to 50 meters, with a trunk diameter of up to 1 meter, and the crown of the tree is very narrow. The bark on young trees is smooth, gray, and becomes rough and scaly on older trees.

These trees grow slowly and when they are 150-200 years old they usually have a trunk diameter of only 25-50 cm. The tree is rarely more than 250 years old, as it is very susceptible to stem rot caused by fungal attacks.

 

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