390 A NATIONAL PLAN FOR AMERICAN FORESTRY 



The greatest damage by fire to the Ohio watershed is the loss of the 

 forest litter, consisting of leaves, needles, twigs, moss, peat, decaying 

 wood, and other vegetative parts. This forest litter acts as a protec- 

 tive soil covering, and is essential in maintaining the porosity of soil 

 and the preservation of channels and minute holes in the topsoil from 

 the pounding action of falling rain. The destruction of litter by fire 

 removes this protection and partially exposes the soil. Furthermore, 

 the heat of fire damages the loose, granular, porous structure of top- 

 soil, by destroying the organic and inorganic colloids which are so 

 important in maintaining this porous flaky condition. 



Very hot fires may burn the forest trees themselves, completely 

 killing them, but this is less serious, in terms of watershed control, 

 than is the loss of litter in every type of fire. The hardwoods tend 

 to renew themselves after fire by sprouting, but repeated burning 

 often prevents more than a brush cover, which while undoubtedly 

 helpful in holding the soil is probably much less effective than the high 

 forest in building up the soil and in preserving favorable conditions 

 of water flow. In the spruce forests at high altitudes particularly, 

 fires have been very destructive. Here the soil is shallow, in places 

 scarcely more than deep duff of undecayed litter. Where this has 

 been burned, the soil itself is practically destroyed. Studies by the 

 Appalachian Forest Experiment Station in West Virginia on the 

 Shavers Fork burn of 1924 indicated that from 12 to 18 inches of 

 spruce and hardwood litter and detritus accumulation was destroyed 

 by fire. On such areas vegetation is slow to return. 



Efforts to control fire took form first in West Virginia in 1908. In 

 Ohio, organized fire protection began about 1921 for the southern 

 forest zone; for southern Indiana, about 1930. Efforts to effect fire 

 control in Kentucky and Tennessee have been inadequate, and protec- 

 tion on federally controlled areas has begun only as the first units were 

 established. Far better and more adequate fire protection is needed 

 throughout the forested portions of this basin, in addition to the 

 excellent work done heretofore. With more adequate fire protection, 

 watershed conditions in this basin should rapidly improve insofar as 

 fire is concerned. 



GRAZING 



The influence on stream flow which grazing exerts in the Ohio River 

 watershed consists of the effect which domestic animals have on woods 

 and soils conditions. Confining stock to small areas of forest results 

 in destruction of forest litter from continual and repeated trampling 

 and cutting by sharp hoofs. The porous condition of the forest soil 

 is then quickly destroyed, not only by the loss of forest litter, but by 

 the heavy weight of the animals themselves. By repeated trampling 

 and moving around, the soil is compacted and firmed until it is 

 impervious except to very slow rainfall. Further damage includes 

 the loss of undergrowth and seedlings which the livestock consume and 

 the barking and trampling of tree roots. 



The greatest influence of grazing is found in the agricultural regions 

 where large numbers of livestock are raised, and are confined on small 

 areas. Within the rougher, more wooded portions of the basin, 

 grazing is a minor factor; but in the agricultural localities it is a very 

 important one. Later reference will be made to grazing. 



