BOTAMCAL GAZETTE. 254 



where only drought-loving plants could exist, the natural result of 

 freedom was the succession of forest growth. Seeds were scattered 

 by winds or animals over acres of cleared land ; if such land became 

 neglected, these, again seeding in time, extended the forest area con- 

 tinually. The tallest growing vegetation, like trees, crowded out the 

 weaker, and the forest naturally crowded out the lower growing and 

 weaker herbaceous i)lants. He illustrated this by reference to the 

 neglected cotton-fields of the Southern States. 



From all this, the speaker said that it was evident that there was 

 nothing in Nature either now or in the past, to prevent the gradual 

 encroachment of the forest over the grassy plains, till long before the 

 white man came here, the whole would have been completely covered 

 by arborescent growth. Were there any artificial causes equal to 

 the exclusion of trees, and yet permiiting an herbaceous growth ? If 

 we were to sow a piece of land in the autumn wtih some tree seed 

 and some seeds of annuals, the latter would be up, flower, mature 

 and scatter their seed to the ground before the next autumn, and 

 many of these seeds would be washed into the earth, or drawn into 

 che earth by insects or small animals. But tree seed would make 

 young trees, which would not again produce seed for ten or more 

 years. If now, at the end of this first season, a fire swept over the 

 tract, the seeds of the annuals which had found a slight earthy pro- 

 tection, would come up again the next summer, again seeding and ex- 

 tending the area. The trees would be burned down, and though per- 

 haps many would sprout, successive burnings would keep them con- 

 fined to one place. In short, under annual burnmgs, herbaceous 

 plants could still increase their area annually, but trees could never gtt 

 far beyond the line they had reached when the annual fire first com- 

 menced. There could be no doubt that an annual burning in a tract 

 destitute of forest growth, would certainly ])revent the spread of tim- 

 ber, or of any plant that required more than a year to mature seed 

 from the time of sowing. Now, if we look at the actual facls, we 

 find that Uie Indians did annually fire the prairies. 



Father Hennepin, the earliest writer on Indian habits, noted that 

 it was the practice in his time. There is but little doubt but this 

 practice of annual burning has been one extending long into the past. 

 What object had they in these annual burnings ? They must have 

 known that the buffalo and other animals on which they were largely 

 dependent for a living, throve only on huge, grassy plains, and that it 

 was to their interest to preserve ihcse plains by every means in their 

 ])ower. Low as their power of reasoning may be, they cnuld not but 

 jiave perceived that wliilc grassy herbage tlirove in spite of fires, perhajis 

 improved under the fiery ordeal, treescould not follow on burned land. 

 What could be more natural than that they would burn the prairies 

 with the object of retaining food for their wild animals ^ If we have no 

 difficulty in rcacliing a jjositivc conclusion so far, we may now take a 

 glance at the early geological times. Mr. Mechan then referred to the 

 researches of Worthen, Whittlcsley and others in Ohio, Illinois and 

 other prairie regions. On the retreat of the great glacier, the higher 



