16- and 18-inch diameter classes. These trees have 

 reached the minimum diameter required by some 

 users of quality logs but are now adding quality 

 growth. In fact, the annual diameter growth is 



4,000 



I 



\; 



\. 



^ 



, \ 



\ 







NORTHERN 



INDIANA 



SOUTHERN 

 INDIANA 



16-18 20-22 24-26 



DBH CLASS (Inches) 



Figure 15. — More sawtimher in large-diameter trees exists in northern 

 Indiana than in the southern part oj the State. 



usually greater than for smaller trees of the same 

 species because the larger trees are usually vigorous 

 and have reached a dominant position in the stand 

 where their crowns get plenty of light. 



The remaining third of the sawtimber volume 

 (nearly 4 billion board-feet) is in the 20-inch and 

 larger diameter classes. These trees are mature or are 

 reaching maturity and as much as possible of the 

 sawtimber harvest should come from them. Northern 

 Indiana has more than half of this volume. More 

 than 90 percent of it occurs in large sawtimber stands. 



Volume by Stand-Size Class 



More than 90 percent of the board-foot volume is in 

 sawtimber stands (fig. 16). Large sawtimber stands 

 have more than 70 percent of the board-foot volume. 

 (Such stands may have as little as 1,500 board-feet 

 per acre but must have at least half the volume in 

 trees 15 inches d. b. h. and larger.) In northern 

 Indiana these stands average more than 6,000 board- 

 feet per acre and in southern Indiana about 5,000. 



About 20 percent of the board-foot volume is in 

 small sawtimber stands, most of which are in southern 

 Indiana. Their average volume throughout the 

 State is about 3,000 board-feet per acre. 



The large acreage of poles, seedlings, and saplings 

 supports much less than 1,000 board -feet per acre 

 (fig. 17) and totals less than one billion board-feet. 

 Paradoxically, the "nonstocked" stands average more 

 than 1,000 board-feet per acre in northern Indiana. 

 These stands are classified nonstocked because they 

 have less sawlog volume than the Forest Survey 

 requires for the sawtimber classification, and heavy 

 grazing and fire have prevented the establishment of 



Figure 16. — A larger percent- 

 o-gf of sawtimber volume in 

 sawtimber stands exists in 

 northern Indiana than in the 

 southern part of the State. 



Indiana's Forest Resources and Industries 



377309—56 3 



13 



