58 IOWA ACADEMY OF SCIENCES. 



shows the greater signs of erosion, because it is exposed to the 

 burning rays of the afternoon sun, while the right bank is in 

 shadow during the hottest part of the day. The effect of this 

 process upon the distribution of timber is evident. The steep 

 bluif-land upon the southern or western bank of a stream is 

 usually heavily wooded, while the flat "bottom" upon the 

 northern or eastern side is often \rery sparsely covered with 

 trees and sometimes quite bare. Before the advent of civiliza- 

 tion the southern bluffs often held the moisture of the winter 

 snows and spring rains until after the season of prairie fires, 

 thus giving the trees sprouting upon their surface a chance to 

 grow, and, when the trees had grown large enough, they fur- 

 ther protected themselves from fire, the surrounding grass 

 being killed out. But the northern bank, which had to face 

 the rays of the spring sun, was well dried by the time the 

 grass on the prairie was dry enough to burn, and so the trees 

 growing upon its surface were destroyed. This is the process 

 which must have taken place during many years before the 

 day when the plow of the first white settler cut the soil of 

 western Iowa. Its effects are still noticeable, but not so 

 noticeable as they must have been at an earlier day. To-day, 

 practically all of the trees in Adair county are of second 

 growth. There are left only a few isolated specimens of the 

 so-called first-growth timber. Since the days when the prairie 

 fires ceased, seedlings have taken root in the fertile flats 

 which form the northern and eastern banks of our streams, and 

 have grown into trees of goodly size, and in some places the 

 southern bluffs have been shorn of their trees. Still, in a gen- 

 eral way, the primitive condition is still noticeable; the timber 

 on the southern bluff is usually larger and thicker than that on 

 the northern bottom. It is noticeable, too, on the prairie — 

 wherever enough of the original brush has been left to indicate 

 anything at all. The hazel and bur oak will grow on a south- 

 ern or western slope, but they are not generally found in such 

 a situation. Usually they seek the northeastern side of a hill, 

 and there they flourish luxuriantly. 



As has been said, there is very little of the first-growth 

 timber remaining in Adair county. The first settlers of the 

 county found along the streams a thick growth of large, well 

 developed trees. Since then almost all of these trees have 

 been removed, until there remains very little timber which was 

 well grown at the time of the first settlement of the county, 



