14 FORESTRY BRANCH BULLETIN NO. 33 



proportions, or pure stands of each species irregularly intermingled. On some aspects, 

 large bodies of pure pine may be found. Where spruce predominates, Douglas fir 

 is found even more frequently than in the spruce stands of Site I, but only to a 

 maximum of five per cent to ten per cent of the stand. Alpine fir (or ' balsam ') 

 is of regular occurrence, inferior in size and quality to the other trees of the stand, 

 but occasionally in small groups becoming the dominant species. Stands on Site 

 II are notably even-aged and uniform in character, which makes the boles slender 

 but comparatively free from branches. The largest proportion of clear lumber can 

 be manufactured from trees of these stands. The even-aged character of many of 

 the stands suggests the connection of some definite event with their origin, and in 

 many cases direct evidence may be found that this event was a fire. 



The pure pine stands nearly always have scattered spruce trees. These grow 

 slowly in youth, anl in even-aged stands are for a long time suppressed by the pine. 

 In young stands, the size of the spruce is smaller than that of the pine, but later the 

 spruce overtakes the pine, and, at maturity of the pine, averages larger in diameter 

 and is growing at a much more rapid rate, as its tolerance has allowed it to keep a 

 comparatively deep crown even in the dense mature stand. 



In general, the ground is drier than on Site I, especially where pine, with its 

 short open crown, enters largely into the composition and admits light and air freely. 

 This promotes a better decomposition of the humus and reduces the thickness of the 

 moss layer. 



As Site III. mav be classified the area on the steeper slopes above Site II, where 

 the dryness and thinness of the soil has checked the growth of the timber, resulting 

 in stands averaging below merchantable size and at best with only the largest of the 

 dominant trees larger than ten inches in diameter. These stands are nearly all even- 

 aged pine stands, but in some cases, especially on northern and eastern exposures, 

 mixed stands of pine, spruce and alpine fir occur. Alpine fir (' balsam ') is the com- 

 monest associate of the pine, and its reproduction usually forms a large proportion 

 of the volunteer growth. White-bark pine and Lyall's larch are of scattered occur- 

 rence near timber line. The number of trees per acre is increasingly high, commen- 

 surate with the smaller development. 



At the tops of ridges, or in the belt just below the timber-line, there may be 

 found stands of scrub trees whose height-growth is so limited that none of the trees 

 come near reaching merchantable size. In some cases these stands are pure pine, and 

 in others are mixtures of pine, spruce and alpine fir, with the exclusively alpine 

 species. These areas might be separately classified as an extra site, or simply included 

 in Site TIT. 



