60 



BULLETIN 55, U. S. DEPAKTMENT OF AGRICULTURE. 



In New Hampshii-e, measurements of over 2,000 acres gave an 

 average yield of 482 board feet for balsam and 1,772 board feet for 

 spruce (Xew Hampshire rule), or nearly 0.8 of a cord of balsam fir 

 per acre, forming about 27 per cent of the entire spruce yield. 

 (Table 50.) 



Table 50. — Average yield of balsam fir over large areas in Grafton County, N. H. 



[New Hampshire log rule.] 



Area (acres). 



Total yield. 



Average yield per acre. 



Spruce. 



Balsam. 



Spruce. 



Balsam. 



107 .... 



Board feet. 

 124, 976 

 273, 840 



94,645 

 170,235 



38,211 

 651,510 

 1,402,856 

 437, 192 

 617,264 

 146, 146 



Board feet. 



63,879 



93,520 



10,925 



14, 715 



846 



67,260 



392,616 



172,494 



174, 386 



84,700 



Board feet. 

 1,168 



2,445 



823 



1,261 



271 



3,429 



2,444 



1,688 



1,384 



949 



Board feet. 

 597 



112 



835 



115 



95 



135 



109 



141 . . . . 



6 



190 



354 



574 



684 



259 



666 



446 . . 



391 



154 



550 







Total (2,233) 



3, 956, 875 



1,075,341 



1,772 



482 







INCREMENT. 



The sample plots in New York and Maine (Tables 46 and 47) 

 showed that mature stands of balsam fir produce annually from 

 one-sixth to one-third of a cord of wood per acre. At such a rate 

 the poorest land produces 10 cords per acre in 60 years, and the better 

 land 10 cords of pulpwood every 30 years. This annual increment is 

 very low as compared with the yields obtainable under forest manage- 

 ment. The increment should be at least two-thirds of a cord, or 

 possibly 1 cord a year. 



MANAGEMENT. 



EFFECT OF PAST CUTTING. 



Balsam fir is so closely associated with spruce wherever it occurs 

 that it is impossible to outline a system of management for one 

 species that will not at the same time affect the other. Both species 

 are almost constantly contesting for the occupancy of the ground. 

 If left to themselves the greater tolerance and more persistent growth 

 of spruce would undoubtedly in the long run secure for it the pre- 

 dominance in the present forests as they formerly did in the virgin 

 stands, before the interference of man. Lumbering, however, has 

 turned the scale of the struggle between the different species in 

 favor of trees of smaller commercial importance. Thus, white pine, 

 the most valuable species of the northeastern forests, was taken 

 first, with the result that it was unable to hold its own against its 

 competitors. Then came the turn of spruce. The latter, in many 



