BALSAM FIE. 67 



ROTATION. 



The difference in the rate of growth of balsam fir and spruce has 

 a direct bearing upon the choice of rotation or proper time of cutting 

 the two species. From the tables it is evident that balsam fir, if 

 its growth is to be utiHzed to the fullest advantage, should not be 

 cut before it reaches an age of about 100 or 125 years, or a diameter 

 of 12 to 14 inches breast high. Cutting balsam fir below 6 or 7 inches 

 means utilization of trees which are still making a fair growth. 

 Spruce, on the other hand, should not be cut before it is 175 or 200 

 years old, since most of its growth is made at the age of from 100 to 

 200 years. The rotation for balsam fir, therefore, should be about 

 100 years, and for spruce at least 175 years. These rotations, of 

 course, would be apphcable only if balsam fir and spruce were grown 

 separately. Since they usually grow together, the practical apphca- 

 tion of these different rotations would simply mean that in cutting 

 over a virgin stand of spruce and balsam fir, the fir should be cut 

 to a younger age, only the older spruce being removed. 



SUMMARY. 



1. Balsam fir forms, on an average, from 10 to 15 per cent of the 

 entire red-spruce stand, or 5,355 million board feet. 



2. Under present methods of cutting, balsam fir is increasing at 

 the expense of red spruce in the second growth throughout the entire 

 range of the two species. 



3. Balsam-fir wood, while to some extent inferior to spruce for 

 construction material, has a definite place in the pulp and lumber 

 industries. 



4. Balsam fir grows much faster throughout its entire hfe than 

 spruce, but is shorter hved and reaches maturity long before the 

 latter. 



5. Balsam fir should be cut at an age of from 100 to 125 years, 

 while spruce, as it grows at present in the wild wood, should be cut 

 at an age of from 175 to 200 years. 



6. The annual increment per acre of balsam fir throughout its 

 range varies from one-sixth to one-third of a cord, or 1 cord in from 

 three to six years. 



7. The best silvicultural system of cutting is that of selection 

 cutting in small groups. The natural reproduction of both spruce 

 and balsam fir is assured under this system, with the possibility of 

 increasing the proportion of spruce in the new stand. 



