220 THE GREAT NORTH-WEST 



abundant, though the millions of the previous thirty 

 years were no longer to be found. Thirty years hence 

 we shall probably have reached the last passenger, unless 

 something is speedily done to save the race. 



The forests of this region deserve a passing notice, 

 for they are very typical American forests. In the beech 

 woods I have been describing, as well as in all other 

 forests in this part of North America, there is no under- 

 wood, and indeed no undergrowth of any kind, not even 

 grass. The ground underneath the trees is composed of 

 the decayed leaves of thousands of years, and in many 

 parts there is a great depth of pure leaf-mould. I cannot 

 say to what depth this mould extends in the virgin forest, 

 but I have dug into it to a depth of sixteen feet in my 

 search for fossils. No wonder the cleared ground requires 

 but scratching to prepare it to nourish the most luxuriant 

 crops. The only encumbrances on the ground are the 

 remains of trees and branches which have been torn down 

 in storms and tornadoes. These, and the trunks of the 

 standing trees, are often covered with moss ; but any sort 

 of creeping plant in the depths of the forest is very rare. 

 The seeds of the trees, as beech mast, or nuts, and acorns, 

 of course fall to the ground every year, and these annu- 

 ally sprout. They are the children of a year only. The 

 life is choked out of all except the few which happen to 

 have fallen where there is a gap in the forest caused by 

 the death of some ancient tree, or its destruction by a 

 storm. At such a spot there is a struggle among the 

 saplings, the strongest winning and occupying the vacant 

 gap, choking in its growth the life out of its competitors. 



Where any one species of tree predominates it holds 

 its own, usually utterly excluding all others, as in the 

 beech woods of this region for instance ; but if by any 

 chance a portion of the forest is destroyed, if only half an 

 acre in extent, the species of tree which springs up to fill 

 the gap will be quite different from that of the surrounding 

 forest. This is a strange circumstance, as is the fact that 



