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five per cent of the black oak and from twenty-five to fifty per cent 

 of the white oaks are infested by borers. Young hickories and elms 

 are especially subject to attacks of the hickory twig-girdler, which 

 often spoils their form by destroying the leader, 



A slight variation of the oak-hickory type is found along the 

 bottoms and gentler slopes of the small stream valleys. The mixture 

 in these situations is more complex ; white oaks are apt to predominate, 

 and many trees of the bottoms are found. The white oaks include 

 overcup, bur, chinquapin, cow, swamp white, and white oak. There 

 are also black oaks, including black, red, and pin oaks, hickories, elm, 

 black and sweet gum, ash, birch, sycamore, honey locust, and walnut. 



Post-Oak Type. — The other type of this region may be called the 

 post-oak type. It is found on what is known locally as "postoaksy" 

 flats. The usual soil is a light gray silt loam on a tight clay subsoil, 

 very impervious, but not a true hard-pan. Drainage is poor and a 

 sour condition prevails. Perhaps the largest and most continuous 

 area is found in the north of Perry and the south of Washington 

 counties, but it is scattered throughout Franklin, Jefferson, Monroe, 

 and St. Clair counties in areas of considerable extent, and to a lesser 

 degree is found in all the other counties of the region. It is often 

 typical of the edge of the true prairie. 



The prevailing forests are open stands of post and blackjack oaks, 

 a few hickories, with occasional patches of pure growth of shingle 

 or pin oak, especially where the ground is wet. The trees are poor 

 in form, with short, rapidly tapering trunks. Blackjack never reaches 

 any considerable size, but the occasional black oaks that are found in 

 the mixture, together with the post oaks, attain merchantable diameter. 

 Shingle oak also makes a very fair growth on these soils. 



These post-oak flats are frequently cut clear for props or posts, 

 so that the younger stands are often even-aged. Since fire has fre- 

 quently followed the cutting, sprout trees predominate greatly over 

 seedlings. Often this young growth forms quite dense thickets, and 

 where fire has been through, the proportion of blackjack is perhaps 

 nearly equal to or even more than that of post oak, — a condition the 

 reverse of the older stands, where the amount of post oak is many 

 times that of blackjack. Pin and shingle oaks are generally of 

 seedling origin. Growth on the whole is very slow. 



Fires have done a great deal of damage in this type, for a number 

 of reasons. The great amount of brush left after clear cutting, the 

 dryness of the soil, and the large contiguous wooded areas, tend to 

 make fires prevalent. Since the soil is naturally poor in humus, the 

 injury in burning out the leaf mulch is all the more severe. The forma- 

 tion of a dense sod and the growth of brush after these fires, combined 



