RANGE AND QUALITY OF SUBALPINE FIR. 49 



SUBALPINE FIR. 



Abies lasiocarpa (Hook.) Nutt. 



A tree of wide range in tiie Coeiir d'Alenes. It is never wholly 

 absent from any portion of the wet valleys of the interior basins and 

 extends up the slopes of the ridges to the highest elevations. As 

 there is no land higher than 2,100 meters (7,080 feet), it can not be deter- 

 mined what the ultimate altitudinal limits of the tree may be in this 

 latitude, but it seems probable that the species would be the last at 

 timber line. In the valleys the tree grows to a height of 20 to 30 

 meters (60 to 1)8 feet), with a diameter up to 50 cm. (20 inches), which 

 it rarely exceeds. At elevations of 1,500 meters (4,900 feet) and 

 upward it seldom goes above 18 meters (00 feet) in height and .'50 cm. 

 (1 foot) in diameter. On the summit of the loftiest ridges it often 

 occurs very much dwarfed. Trees which do not reach a stature above 

 2 to 3 meters (0.7 to 9.8 feet) bear cones and show an age of 50 to 00 

 years. This is more due, however, to a rocky and unproductive soil 

 than to nearness of altitudinal limits. The tree requires an abun- 

 dance of moisture and at low elevations a northern or eastern exposure. 

 Given this, the lower limit of its range will be the lowest levels of the 

 Cceur d' Alen.es, about 050 meters (2,100 feet). In the basaltic areas of 

 the St. Mary and St. Joseph valleys it is frequently found associated 

 with a dense yellow-pine forest. In the valleys the tree never forms a 

 forest of pure growth. It is always scattered among the other conifers, 

 lint on the mountain slopes and summits, at 1,500 meters (4,000 feet) 

 elevation and upward, there are often large tracts where the species 

 forms fully 00 per cent of the forest. This is especially the case on the 

 ridges of the i^orth Fork basin. The tree has always a large crown, 

 with rarely a clear trunk, though the branches for a distance of 5 to 

 meters (10 to 20 feet) from the ground may be small and dead. More 

 often they are green quite to the ground. It is of short-lived growth, 

 and the large individuals are mostly rotten in the center. The wood 

 of the tree when it grows in the valleys is very soft and sappy and of 

 no value, even for fuel. On the ridges, owing to slower growth, the 

 wood is denser and contains less sap. If cut and allowed to season, 

 it shrinks and becomes so dense that only with ditliculty can a nail be 

 driven into it. It can then be used for various purposes, such as tim- 

 bering mining tunnels and shafts, and is fully as durable as wood from 

 the yellow pine. The bark of these two species of fir is abundantly sup- 

 plied with resin vesicles, and they are therefore commonly known as 

 balsam firs. They are frequently confounded with each other, but, 

 aside from other characters, they may be readily separated by the 

 position the vesicles occupy in the bark. On the white fir these are 

 quite superficial and appear as raised blisters, while on the subalpine 

 fir they are sunken, and rarely appear elevated above the surface of 

 the bark. 



