REPORT ON FORESTS. 129 



CAUSE OF PRESENT CONDITION. 



Many attempts have been made to account for the present 

 condition of the Plains, but these explanations have not been 

 altogether satisfactory. Some have attributed the form of the 

 Pine to a lack of certain mineral constituents in the soil neces- 

 sary to the growth of trees. This theory, however, is disproved 

 by chemical analyses of the soil made by the Geological Survey, 

 which show no greater poverty than is common to the surround- 

 ing region. The theory that fire, combined with the effect of 

 very poor top-soil and a hard subsoil, is tlie efficient cause, has 

 also been advanced, and certainly fire has been a very large 

 factor in bringing about the present condition of these areas. 

 Sufficient emphasis, however, has not been laid on the fact that 

 the Pine is for the most part of sprout origin, and on the causes 

 of the prostrate form of young seedling trees. 



If the Plains have been in their present condition since the 

 country was first settled, they were probably first burned over 

 by the Indians, who were in the habit of camping in the neigh- 

 borhood, as their shell-heaps show. We know that the western 

 forests are often burned by the Indians to-day, and there is 

 reason to believe that piany even-aged stands of Pine in the 

 Eastern States date their origin from fires set by the Indians or 

 by lighting. It is not unreasonable, therefore, to suppose that 

 these high rolling plains were originally stripped of their forest 

 cover in this way. The Pines, which probably returned by seed 

 after the first fire, were burned over again and again, and their 

 stumps sent up sprouts which became more and more feeble 

 after successive fires. Many old stumps, as already pointed out, 

 became exhausted and died after repeated sprouting. Their 

 place was taken by seedlings, and in this way the ground re- 

 mained stocked with Pine. 



This does not explain, however, the prostrate form of the 

 young seedlings and many of the older trees. This peculiarity 

 is not confined to the Plains alone, for Pine seedlings growing 

 on bare sand in exposed situations in the neighborhood of the 

 Plains show the same tendency. These seedlings exhibit a 

 remarkable similarity to the forms assumed by trees near the 

 timber line on high mountains. It is a fair inference that the 

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