24 A PRIMER OF FORESTRY. 



covers the ground. As it grows older fires destroy 

 patches of it here and there, and in time every patch 

 is covered again with a younger generation of even 

 age. After many years the forest which sprang up 

 after the first fire has become broken into a number of 

 even-aged patches without uniformity in size or regular 

 gradations in age. 



Now let us suppose that this land was taken in hand 

 by the Government when the lodgepole pine first came 

 in, and that the lodgepole reaches its maturity at 80 

 years. If the Government forest officers had divided 

 such a forest into eighty parts, and then had cut the 

 timber from one part each year, after a time they 

 would have had eighty divisions, each covered with 

 even-aged forest, but differing in age among them- 

 selves from 1 to 80 years. Every } T ear one part would 

 reach the age of 80 years and would be cut, and evi- 

 dently the other seventy- nine parts would always be 

 stocked with trees from 1 to 79 years old. 



When the trees on one of the eighty divisions just 

 mentioned become ripe for the ax, provision must be 

 made for a new crop. This would be a very simple 

 matter if the forest on that division could be repro- 

 duced naturally in one } r ear, but that is practically 

 impossible. Such rapid reproduction can be got only 

 by planting, which is chiefly useful in the United 

 States for making new forests and restoring injured 

 forests, not for renewing old ones. Reproduction 

 from the seed of the old trees is the only kind we need 

 consider here. In order to bring it about a few ripe 

 trees are first cut down, to prepare a seedbed by giv- 

 ing light to the soil, and to fit the seed trees to bear 



