706 A NATIONAL PLAN FOR AMERICAN FORESTRY 



of camp fires completely remove the surface humus which provides 

 organic matter for the underlying soil and causes pronounced com- 

 pacting, thus creating such unfavorable conditions for plant growth 

 that many fine big trees, often several centuries old, are killed directly 

 or by root fungi or other parasites that take advantage of these ad- 

 verse conditions. Constant and indiscriminate use of automobiles 

 in such areas leads to mechanical wounding of many trees and to soil 

 poisoning by dripping of oil and gasoline. More must be known 

 particularly as to the way in which campers and tourists affect dis- 

 eases by changing soil conditions. The loss of two or three dominat- 

 ing trees on a camp ground may cause more real reduction in value 

 than the killing of as many acres of remote timberland. Intelligent 

 location and planning of sites for this intensive use and more ade- 

 quate supervision of their occupancy will be essential to prevent 

 damage. 



DETERIORATION OF KILLED TIMBER 



Occasionally there are extensive stands of mature timber that have 

 been killed by such agents as fire, insects, windthrow, and more rarely 

 introduced parasitic fungi. Killed timber rapidly deteriorates from 

 checking, staining, wood-boring insects, and decay, the rate of 

 deterioration varying with the tree species involved. Prompt removal 

 and utilization of such timber is the only effective method of salvage. 

 This is not always possible either because of economic conditions or 

 because the aggregate volume killed while large is so scattered that 

 it cannot possibly be salvaged at a profit. Where bark beetles have 

 done the killing, stain fungi that entered with the beetles are already 

 established in parts of the sap wood by the time the trees died. 



In 1921 more than 3.5 billion board feet of very large merchantable 

 timber of high quality was windthrown on the Olympic Peninsula in 

 Washington. At the end of the first season of exposure the loss in 

 Douglas fir amounted to 1 percent, in Sitka spruce to 3 percent, and in 

 western hemlock to 13 percent. By the end of the sixth season the 

 losses were 19, 36, and 78 percent, respectively. From the fourth 

 season on, most of the loss was caused by decay, and during the first 

 three seasons by blue-staining fungi and wood-boring insects. 



Balsam fir killed by the spruce bud worm in northern Minnesota 

 and Wisconsin is so quickly decayed that stands are not worth 

 salvaging after the third year of exposure. 



Chestnut presents the most important problem in timber salvage 

 which has ever faced the United States. The chestnut blight is 

 responsible for the death of millions of acres of chestnut timber from 

 Maine to Alabama. In New England and the Middle Atlantic 

 States where the disease first struck, fair prices simplified the market- 

 ing problem. In the southern Appalachians, where the menace was 

 not appreciated by timber owners until after the World War, a glutted 

 lumber market accompanied by ridiculously low prices has made 

 utilization difficult. 



Fortunately chestnut heartwood is unusually durable; investiga- 

 tions have shown that the tannin content is not materially less in 

 trees dead 20 to 30 years than in living trees. For the first 10 years 

 after a tree is killed by the blight, the loss in wood volume from decay 

 is not important. After that time, windthrow increases markedly 

 and the down trees deteriorate at a much more rapid rate than those 

 left standing. 



