182 ILLINOIS STATE ACADEMY OF SCIENCE 



region since the settlement by white men about 1840. Fires, 

 for example, starting at the railroad on the north of the 

 Pine woods in Pine Creek Township, run not infrequently 

 southwards through the area where white pine reproduc- 

 tion generally occurs in the oak woodland adjacent, and 

 are a factor in the successional changes, but here again an 

 uninvestigated factor. There is no evidence, however, in 

 the Rock River woodland region of any such periodical re- 

 currence of fires as would be effective directly or indirectly 

 in bringing about a swing in the successional stages such as 

 has been referred to. The supposed damage to woodland 

 growth by unfavorable climatic changes and plant disease is 

 said to have eventuated economically as follows. Tne first 

 settlers located themselves in the prairie groves and in 

 the woodland along streams, having a prejudice against the 

 sod of the prairie for farming and also because of the 

 water and the protection from wind afforded by the woods. 

 These early settlers, however, were few in number and did 

 not greatly alter the original extent of the wooded area of 

 the county. Later settlers took up the prairie soil chiefly. 

 Thus the wooded area of the county was preserved without 

 much change in extent until a still later date. Then, ac- 

 cording to the local accounts, in about the period of 1880- 

 1900, the damage to tree growth by unfavorable seasons 

 and disease caused much clearing to be made in the 

 wooded areas. 



It has been established by meteorologists that no perma- 

 nent change is taking place in the climate of the country 

 within historic time. Within geologic time periods a change 

 may eventuate. Records available in this country are too 

 short to afford any definite indication of any but short 

 period fluctuations. The longest cover a period of only 

 about 100 years and very few stations have records of 

 more than 50 years in length. 



Unfortunately there is no more than some fragmentary 

 records of meteorological conditions in Ogle County. Not 

 far from this county, however, in the same general locality, 

 there does exist one of the oldest and longest series of 

 records for both precipitation and temperature in the entire 

 state. These are for Marengo (formerly Riley) near the 



