234 



Table XIV. — Growth of Oaks and Basswood on Prairie Upland, Illinois. 



Size at Specified Ages. 



Data. — Stump counts taken in northern and central Illinois by Ziegler, 

 Stump height^l'-2', 



Black oak from 14 stumps, white oak from 62 stumps, and basswood from 

 6 stumps. Curves. 



The figures for swamp Spanish oak (Quercus pagodaefolia) are 

 divided into three classes : ( i ) dominant trees, or those which were 

 especially vigorous and had overtopped the others; (2) intermediate 

 trees, which might be considered as the average trees; and (3) sup- 

 pressed trees, or those which were overtopped by the other two classes. 

 Individual trees show a much faster rate of growth than is indicated 

 even by the dominant figures, but the figures as given in all these tables 

 are averages smoothed off by curves. 



The Spanish and pin oaks and elm were all growing on fair bottom- 

 soils, which are designated as quality i. The pin oaks were largely 

 young second-growth trees, while the Spanish oak and elm represent 

 the growth of trees in older, more uneven-aged stands. 



The figures given for the growth of black and white oaks and bass- 

 wood on the edge of the prairie upland were obtained by a former 

 party that worked in the state. 



Forest Protection 



FIRE 



Fire is the most serious enemy with which the forester has to con- 

 tend. Proper management of woodlands is impossible without protec- 

 tion from this danger. Fortunately, hardwood forests are subject only 

 to surface fires, which are easier to prevent and to put out than any 

 other kind. They are nevertheless very injurious, and their worst 

 consequences are those which are least conspicuous. These comprise 

 the damage to the soil, to reproduction, and to young growth. 



