Total volume of growing itock. — Total volume of 

 growing stock in 1950 was 2.8 billion cubic feet — 683 

 cubic feet per acre. In Indiana the stands average 

 858 cubic feet per acre in the north and 613 in the 

 south. 



Growing-stock volume by stand size. — The large saw- 

 timber stands average little more than 1,000 cubic 

 feet per acre and contain 58 percent of the growing- 

 stock volume. The small sawtimber stands average 

 about 900 cubic feet per acre and contain 23 percent 

 of the growing stock. Pole stands average 372 cubic 

 feet per acre and have 18 percent of the growing-stock 

 volume. Seedling and sapling and nonstocked stands 

 average 48 and 69 cubic feet per acre respectively and 

 cover the remaining 1 percent. 



Growing-stock volume by tree size.- — Thirty-two percent 

 of the growing-stock volume is in poletimber trees 

 (fig. 21); 26 percent is in small sawtimber (12 and 14 

 inches d. b. h.); 20 percent is in 16- and 18-inch saw- 

 timber; and the remaining 22 percent is in trees 20 

 inches and larger in diameter. If maximum growth 

 is to be obtained, a larger percentage of the growing- 



D.B H^ CLASS (Inches) 



Figure 21. — A high percentage of Indiana's growing stock is in 6- 

 through 74-inch diameter classes. Proper management of the trees 

 in these diameter classes could rapidly improve the stocking and 

 quality of sawtimber stands. 



stock volume should probably be in 16- and 18-inch 

 trees. 



Total volume of sound wood. — Stands average about 

 1,027 cubic feet (16 cords) of sound wood per acre 

 in trees 5 inches and larger in diameter including hard- 

 wood limbs and cull trees as well as the merchantable 

 stems that are considered growing stock. Limbs alone 

 average about 276 cubic feet (4 cords) per acre. 



Timber Growth and Mortality 



Sawtimber Growth 



The net growth of sawtimber was 551 million board- 

 feet in 1950. Fifty-five percent was growth on trees 

 already of sawtimber size. The remaining 45 percent 

 was ingrowth. Ingrowth is the total board-foot 

 volume of trees that grew into the sawtimber class 

 during the year. The net growth amounted to 5 

 percent of the sawtimber volume. 



Average growth per acre was 185 board-feet in the 

 northern part of the State but only 115 board-feet in 

 the southern part. The better growth in the north 

 indicates the advantage of maintaining a higher 

 volume of growing stock. In both sections the growth 

 probably could be doubled by practicing better 

 forestry. Better protection from fire and grazing 

 \vould help greatly to improve the stocking of seed- 

 lings, saplings, and poletimber. Mortality could be 

 reduced and the growth rate increased by removing 

 defective and slow-gi^owing trees. 



To get high-grade logs it is necessary to delay cut- 

 ting the well-formed trees until they are 16 to 18 

 inches in diameter or larger. Only 14 percent of the 

 net board-foot growth is now in high-quality logs. 

 In well-managed stands probably as much as 30 to 40 

 percent of the sawtimber growth is in high-quality 

 logs. Since total volume of sawtimber growth could 

 probably be doubled \sithin a fe\v decades by good 

 forestry practices, value might be tripled or quad- 

 rupled by increasing the percentage of high-quality 

 sawtimber. 



Gro ivth of the Growing Stock 



Net growth of stock was 107 million cubic feet, or 

 about 26 cubic feet per acre in 1950. By better 

 stocking and management than used previously, the 

 stands could probably be made to grow as much as 

 60 to 80 cubic feet per acre annually. 



16 



Forest Resource Report No. 10, U. S. Department of Agriculture 



