GENERAL CONDITIONS 1 15 



Stands in this subtype range from 60,000 board feet p>er acre on 

 the moister sites within its range to 2000 board feet on the drier 

 sites with an average of 20,000 board feet. 



The sugar pine-fir subtype, on the other hand, is character- 

 istic of the northern part of the type's range and is found where 

 the climate is moist and cool enough for Douglas fir. The 

 average stand p)er acre is 30,000 board feet with a range from 

 150,000 board feet to 5000 board feet. The composition by vol- 

 ume is as follows: 



Per cent 



Sugar pine 30 



Douglas fir 40 



White fir 30 



This subtype occupies a much smaller area than the sugar pine- 

 yellow pine subtype. 



Growth within the type is summarized in the following table: 



25 years 



50 years 



75 years 



100 years 



Diameter 



Sugar 

 pine 



Inches 



I 



s 



10 



18 



Yellow 

 pine 



Inches 



4 



8 

 14 

 20 



3 



Incense 

 cedar 



Inches 



I 



S 

 8 



14 



Height in feet 



10 



35 

 60 

 92 



IS 

 45 

 6S 

 94 



5 

 20 



35 

 65 



Yield per acre 

 all species 



board feet 



400 



1600 



4000 



7300 



These figures are low because they have come from the measure- 

 ment of virgin timber. Stands under management can be 

 expected to grow much more rapidly because the better species 

 could be aided to dominate the poorer individuals at an early age 

 and thus shorten materially the struggle for supremacy. The 

 yield, particularly, can be much increased. This will come, 

 however, by making the stands more dense so that more trees 

 will grow per acre. Virgin stands have been greatly decimated 

 by fires, insects and fungi but there is no reason why reasonable 

 care may not prevent the greater part of these losses. 



Fire is, as always, the main source of damage in this type. On 

 account of the openness of the stand fires do not, however, get 

 off the ground and bum the tops except in rare cases where a long 



