A NATIONAL PLAN FOR AMERICAN FORESTRY 409 



low type of cover, but frequent fires prevent the development of a 

 good litter cover. 



For the Ozark-Ouachita section as a whole, grazing is not a factor 

 of great importance in watershed conditions. Some hardwood forests 

 are grazed, with consequent opening of the stand and dissipation of 

 the litter. Cattle are turned loose on pine lands, also, especially in 

 the Kisatchie Hills section of northern Louisiana, but not in sufficient 

 numbers to create critical conditions through depleting the minor 

 vegetation. The practice of burning for the purpose of range better- 

 ment is the most serious factor connected with grazing. 



FRINGE FOREST 



In Missouri, Oklahoma, Kansas, and northern Texas, extensive 

 areas of woodland have been cleared for agriculture. As settlement 

 increased the practice of burning the woods became prevalent. 

 Under burning, humus conditions deteriorated and the perennial 

 herbs gave way to annual grasses. Overgrazing, also, has greatly 

 depleted the vegetative cover and in the stands thus opened litter 

 cover cannot form because winds scatter the leaves. 



The extent of fires in the fringe forest type is indicated by fire 

 records for Oklahoma, where the fringe forest makes up about two 

 thirds of the total forest area. The records do not separate the wood- 

 land type from the commercial forest, but probably at least half and 

 possibly two thirds of the fires recorded occurred in the woodland 

 type. In 1931, 7,600 forest fires in Oklahoma burned almost 2% 

 million acres of the 12% million acres of forest land in the State and 

 did damage to the extent of more than $3,000,000. This damage 

 estimate takes no cognizance of watershed values impaired or 

 destroyed. 



The effect of fire in this type is shown by investigations recently 

 made at the Red Plains Erosion Experiment Station, near Guthrie, 

 Okla., which are described in detail in the discussion, " Consequences 

 of Disturbing the Forest Cover. " These investigations showed that 

 the run-off from a burned plot of post-oak timber was more than 110 

 times as great as the run-off from a similar unburned plot. Erosion 

 similarly removed 15 times as much soil from the burned area. 

 Although the litter found in post oak woodland is not so dense or so 

 effective in limiting run-off as that in forests of many other species, 

 in this experiment it showed great value for flood control. 



Erosion is common on the upland cultivated soils, especially on 

 those that are hilly or rolling and not terraced. As a result of this 

 erosion heavy silt loads are carried by the streams of southwestern 

 Missouri and eastern Kansas. Of the two Hanceville soil types the 

 State forester of Oklahoma said: "Much of the land when cleared is 

 so subject to erosion that only a comparatively few crops can be 

 raised before it has to be abandoned." In the Wichita and Arbuckle 

 Mountains of central Oklahoma, agriculture on steep hill lands has 

 caused both sheet and gully erosion. Many of the eroded lands have 

 been abandoned. On these lands a forest cover is slow to return. 



In 1930 an erosion survey by the Oklahoma Agricultural College 

 disclosed that of the approximately 16 million acres of cultivated land 

 in the State 13 million acres was subject to excessive washing, 6 

 million acres had reached the gullying stage, and 374,000 acres was 



