78 Kansas Academy of Science. 



water is absent, willows, cottonwoods and other trees soon take 

 possession of the river-bed and its banks. 



The river-bottoms are inhabited by great numbers of gophers. 

 These throw up small mounds of earth, sometimes several yards in 

 diameter. Here seeds of trees sprout and a forest results. For- 

 merly the fire prevented much development of this type of forest. 

 But at present gopher hills are a very important factor in the out 

 extension of the forest belts. The Green ash is most aggressive in 

 taking possession of these hills. Rough-leaf dogwood is also im- 

 portant. I know of a number of young forests which have de- 

 veloped in this way since prairie fires have ceased. During the 

 regions of the fires the Green ash could be found far out in the 

 prairie occupying the isolated gopher hills, but burned down so as 

 form a sort of woody crown-former. 



• The Creek Bottom. — Along the smaller creeks there is usually 

 only a narrow belt of forest on both banks, extending from the 

 water up to the flood-plain level. The presence of this forest is 

 due to the moist condition of the creek bank and the layer of al- 

 luvium which is deposited at each ordinary rise of the water. The 

 alluvium not only covers the grass and other herbs but gives a very 

 favorable soil for the development of woody seedlings. Where 

 there are sharp bends small, low bars are formed, subject to frequent 

 overflow, and these are covered by a forest of the type in the river 

 valley on a smaller scale. The succession of trees is however not 

 the same. The important tree is the box-elder, which takes the 

 place of the cottonwood along the river. The forest may also ex- 

 tend outward on gopher hills, and the Green ash, so far as it ex- 

 tends up the creek, is the main tree to take possession. The 

 outward extension in the creek bottoms is very marked since 

 prairie fires have ceased. Some low, narrow flood-plains may be 

 entirely wooded, but this is exceptional at present. 



The creek-bank forest is continually progressing up stream, and 

 this extension is now very rapid because of the large amount 

 of sediment brought down from plowed ground. On Mulberry 

 creek, near the upper limit of the timber belt, the alluvium was 

 very abundant and covered with a luxuriant growth of large weeds. 

 The beginnings of a forest were shown by the presence of large 

 numbers of young trees of box-elders, cottonwood, and Peach-leaf 

 willow. 



The Wooded Bluf. — The steep bluffs along the river, creeks and 

 larger ravines furnish another physiographic form favorable for 

 forest development. The bluffs most completely wooded face the 



