Saplings reaching poletimber size accounted for 

 about 13 percent of the growth. Poletimber, which 

 made up only 32 percent of the growing-stock vol- 

 ume, accounted for 47 percent of the cubic-foot 

 growth. The remaining 48 percent was on sawtimber 

 trees. 



On the average, sawtimber trees are growing about 

 2 inches in diameter in 10 years, poletimber trees 

 about 1 % inches. 



Mortality 



Losses of growing stock other than by cutting in 

 1950 were estimated at 6.2 million cubic feet, which 

 includes 19 million board-feet of sawtimber size. 

 These losses, amounting to less than 1 percent of the 

 growing-stock volume, are not large but occur an- 

 nually and can be reduced by better protection and 

 management. This waste occurs because some trees 

 die or become susceptible to diseases and insects on 

 account of suppression — competition for light and 

 growing space. Fire (fig. 22) and grazing also kill 

 many trees and damage others leaving wounds where 

 decay fungi and insects can enter. Many trees fall or 

 are broken during wind and ice storms. 



In Indiana, timber mortality can be reduced by 

 greater effort to prevent fires. Most fires are prevent- 

 able because 75 percent of them are caused by smokers 

 or debris burners. The other 25 percent are started 

 by railroads, campers, loggers, and other miscellaneous 

 causes. From 1947 to 1951 an average of 8,000 acres 

 burned annually, but in 1952 nearly 28,000 acres 

 burned. About half of the burned area was timbered. 



The Forest Survey crews estimated how much 

 grazing occurred on every forest field plot. An area 

 was "heavily grazed" if (1) grazing had eliminated 

 the reproduction, (2) grass sod was generally estab- 

 lished, (3) a distinct grazing line was formed by stock 

 browsing the lower branches, and (4) it appeared that 

 continued grazing at the same intensity would even- 

 tually eliminate the forest. Heavy grazing was prac- 

 ticed on 12 percent of the forest land in the State. 

 Almost all forest land shows signs of being grazed at 

 least lightly. However, heavy grazing is most evident 

 in northern Indiana where nearly 24 percent of the 

 forest land was grazed heavily as compared to 7 

 percent in southern Indiana. When land is managed 

 for timber production, elimination of livestock from 

 the woods is generally desirable. 



Diseases and insects, although not now causing 

 noticeable losses but always present in the forests, are 

 more serious than ordinarily recognized. Diseases and 

 insects contribute to the annual tree mortality and 

 reduce the quality and usable portion of many mer- 

 chantable trees. Rot can be controlled best by pro- 

 tecting the stands froin fire and grazing and by cutting 

 the trees when they mature before they become de- 

 fective. The Dutch elm disease has killed many elm 

 trees, and oak wilt is a threat to the oaks.^ ^ 



Timber Cutting 



The volume of timber cut from Indiana forests in 

 1949 was estimated at 254 million board-feet of 

 sawtimber plus 157,000 cords of poletimber, making 



Figure 22. — Fire damages the 

 thin hark of many trees and 

 either kills them or causes 

 wounds where decay fungi and 

 insects can enter. 



Indiana's Forest Resources and Industries 



17 



