Primary Growing Stock 



The primary grooving stock is that part of the 

 stand which either has significant merchantable 

 value for products other than fuel Avood or has 

 prospects of growing into material of value in the 

 future. It consists of the net volume of live saw- 

 timber trees and live pole-timber trees from stump 

 to a minimum 4-inch top, but excludes all limb 

 wood. 



Roughly one-third of the primary grooving stock is 

 in the form of saw timber, two-thirds in the form 

 of cordwood below sawlog size. Most of the cord- 

 \vood is in pole timber, that is, in trees ranging in 

 diameter breast high from 5.0 to 8.9 inches in the 

 case of softwood species or 5.0 to 10.9 inches in the 

 case of harchvoods. A small part of the cordwood 

 consists of the tops of soft\v'ood saw-timber trees. 



Most of the saAvlog volume is in saw-timber stands 

 but the larger share of cubic-foot volume is in stands 

 below saw-timber size (table 11). 



SAW TIMBER 



The present volume of saw timber— 40 billion 

 board feet— is only about 5 percent of the original 

 volume in the region (26). It is only one-third of 

 that rejDorted in 1918 (57), and somewhat less than 

 reported in 1936 and 1945 (39). Not too much 

 significance should be placed on relatively minor 

 changes in recent years, however, because they have 

 been affected by the standards of measure by which 

 the timber has been estimated. ^ The important 

 point is that the original timber stand has been 

 largely liquidated and the jDresent volume of second 

 growth is only about half that required to sustain 

 a high and steady yield of saw-timber products. 



Table II.— J^olume of primary grmritig slock on commercial 

 forest land in the Lake States region, by stand class, 1950 



^Original timber estimates, as well as those of 1918, ^vere in 

 terms of Scribner decimal C scale and overlooked considerable 

 volume of timber other than white and red pine. From 1936 

 on, estimates were by International 14 -inch rule, which is 

 roughly 15 percent higher than Scribner decimal C. Between 

 1936 and 1950, certain changes were made in specifications 

 for saw timber in the interest of standardizing estimates for 

 the eastern United States. One change— excluding hard^vood 

 trees in the 10-inch diameter class from the saw-timber 

 estimate and raising the minimum diameter for aspen logs 

 from 6 to 8 inches— was largely responsible for the 20-percent 

 reduction in saw-timber estimates between 1945 and 1950. 

 On the other hand, a loosening of specifications for low-grade 

 hardwood logs (to reflect the trend toward closer utilization) 

 has the effect of increasing the estimate of saw-timber volume 

 in the southern forest zone, which has a preponderance of 

 farm woods. 



Stand class 



Live saw timber 



All primary 

 growing stock 













Total 

 volume 



Average 

 per acre 



Total 

 volume 



Average 

 per acre 





Million 





Million 







hoard jeet 



Board feet 



cubic Jeet 



Cubic feet 



Saw timber . 



31,400 



5,320 



8,950 



1,520 



Pole timber _ 



5, 550 



580 



6,700 



700 



Seedlings and saplings 



2,150 



100 



3.500 



160 



Poorly stocked and deforested .. 



900 



70 



850 



70 



Total 



40. 000 



800 



20. 000 



400 



Average quality of the hard-wood sa^v timber is 

 rather poor. In 1936, about 30 percent of the total 

 hardwood volume was in No. 3 logs, the minimum 

 acceptable for railroad ties and rough lumber. 

 With current Survey standards, the proportion is 

 even larger. 



Michigan has the largest share of remaining saw 

 timber, Minnesota the least (table 12). Hardwoods, 

 predominantly sugar maple, oak, aspen, and elm 

 make up 70 percent of the total volume. Hemlock, 

 Avhite pine, and jack pine are the predominant 

 softwood species. 



Table \2.— Board-foot volume of saiv timber on commercial 

 forest land in the Lake States region, by species, 1950 



Species 



Region 

 total 



Minnesota 



Wisconsin 



Michigan 



Softwoods; 



White pine. .... 



Red pine... _ 



Million 

 board feet 



2,400 

 900 

 2,000 

 3,900 

 1,300 

 1,300 

 200 



Million 

 hoard feet 



1,000 

 400 



1,400 







700 



400 



100 



Million 

 board feet 



700 

 200 

 300 

 900 

 100 

 300 



Million 

 board feet 



700 

 300 

 300 



Hemlock 



3,000 

 500 



Balsam fir 



600 





100 







Total., 



12,000 



4,000 



2,500 



5,500 



Hardwoods; 



Sugar maple 



Yellow birch 



7,900 

 2,000 

 1,900 

 1,100 

 3,000 

 5,300 

 3,200 

 3,600 



300 

 100 

 500 

 

 700 

 700 

 1,400 

 800 



2,500 

 500 

 500 

 100 



1,200 



3,200 

 800 



1,200 



5,100 

 1,400 



Basswood „ 



Beech 



Elm 



Oak '..._ 



Aspen . 



900 

 1,000 

 1.100 

 1.400 

 1,000 





1,600 







Total * 



28,000 



4,500 



10.000 



13,500 



All species.. 



40,000 



8,500 



12,500 



19,000 



22 



' Appro.vimalely Iwo-thirds of all oak is red oak. 



Forest Resource Report No. 1. U. S. Deparhnent of .igricidttne 



