8 CIRCULAR 7 91, IT. S. DEPARTMENT OF AGRICULTURE 



The area of the original conifer-forested swamps in Minnesota has 

 been estimated to have been 6,000.000 9 acres. In addition, the original 

 forests were estimated to include 6,300,000 acres of the so-called spruce- 

 fir type. Black spruce occurs rather generally in this type. 



Present Area and Volume 



Land clearing for agriculture, logging, and indiscriminate burn- 

 ing have greatly reduced the area and volume of black spruce timber 

 (fig. 7). In 1934 only about half of the original coniferous swamp 

 supported a forest type similar to the original forest, and only one- 

 sixth of the original spruce-fir type could still be so classified (table 

 1 ) . 9 In the coniferous swamp type 1,529,800 acres were classified as 

 having a cover mainly composed of black spruce. Until the de- 

 forested and aspen-covered swamps are restored to black spruce — a 

 very slow process at best — the timber in the remaining iy 2 million 

 acres of black spruce swamp, together with the black spruce timber 

 intermingled in the spruce-fir type, must serve as the principal Minne- 

 sota source of black spruce wood. 



Figure 7. — Burned out peat land in northern Minnesota. 



It was estimated in 1934 that Minnesota had 5,429,000 cords of mer- 

 chantable black spruce pulpwood — i. e., trees large enough to produce 

 two 100-inch bolts to a 4-inch top inside bark — distributed in Forest 

 Survey economic units as follows: (1) Cloquet, 305,000; (2) Central 

 Pine, 398,000 ; (3) Rainy River, 1,911,000; (4) Superior, 2,653,000; (5) 

 Central Hardwood, 17,000; and (6) Prairie, 145,000, The great bulk 



: See footnote 6, p. 3. 



