26 Forest Club Annual 



SUB-ALPINE TYPE. 



This type is made up principally of Engelmann Spruce 

 (Picea engelmanni Engelm.) and Alpine Fir (Abies lasiocarpa 

 Nutt.). It requires a very moist, cool site and hence occurs on 

 the northerly exposures above 9,000 feet in elevation. Along 

 stream courses Engelmann Spruce may be found as low as 

 8,000 feet in mixture with White Fir and Douglas Fir. It rarely 

 occurs in merchantable quantities, however, below 9,000 feet 

 elevation. Wherever the fir type merges into the sub-alpine type, 

 the Douglas Fir comprises a large part of the stand. As the 

 elevation increases the per cent of Douglas Fir decreases, until 

 finally it ceases to be of any inportance above an elevation of 

 10,000 feet, except in the restocking of burnt-over areas. Al- 

 pine Fir is a minor species rarely forming more than 10 per cent 

 of the total stand. Engelmann Spruce is by far the most im- 

 portant species, and occurs in stands which often run as high 

 as 90 to 110 mature trees on a single acre. This is true only in 

 the virgin, unburnt areas. Since this type grows only at the 

 higher elevations it occupies the steeper and more rugged slopes. 

 Rock outcrops are frequent, rendering logging operations much 

 more difficult and expensive. Often large areas are inaccessible 

 because of the adverse nature of the topography. 



Almost all of this type has been burnt over at least once 

 within the last natural rotation, and hence there is usually con- 

 siderable Aspen as well as some Mexican Locust mixed in with 

 the permanent species. The dense nature of the stand naturally 

 causes a heavy layer of litter and there is usually considerable 

 underbrush, although it is rarely as dense as that in the typical 

 fir stands. Prolific reproduction in all stages is usually character- 

 istic of Engelmann Spruce and Alpine Fir, as well as Douglas 

 Fir at the elevations where these species occur in this type. 



The reproduction combined with the litter forms conditions 

 very similar to that of the fir stands in regard to fire danger. 

 In addition, a large per cent of the Alpine Fir over 12 inches 

 d. b. h. is in poor condition because of insect attack. As the 

 affected tree approaches maturity it loses its vigor and gradually 

 begins to die. Just as the diseased White Fir increases the danger 

 of fire started by lightning in the fir type so the insect-attacked 

 Alpine Fir increases this danger in the sub-alpine type. Conse- 

 quently, even though this species forms only a small proportion 

 of the stand, the danger of fire is much more imminent because 

 of its occurence. The danger from lightning-struck trees is also 

 greater because the type occurs on the mountain ridges where 

 lightning strikes most frequently. It is not uncommon to find 



