PEACTICAL FORESTRY. 



17 



the area cut over in any one year is small, and the reproduction is 

 provided for by natural seeding in the openings of the forest 



The group system.— It often happens that all the trees of a small 

 group in the forest are killed by fire or insects at about the same 

 time. In the opening thus made the ground is quickly covered with 

 young growth, which extends back under the old trees as far as the 

 hght will permit. The seedlings are usually tallest, strongest, and 

 most numerous directly under the middle of the opening, and gradu- 



Fig. 9.— Group of spruce under beech. Germany, 



ally decrease at the sides. If the wind should throw some trees at 

 the edges of such an opening the young growth would gradually 

 extend, and if the same thing should continue to happen in the end 

 aU the old trees would have disappeared and their places would have 

 been taken by" young growth. The group system is an imitation 

 of this process. 



Under the group system openings are made here and there in the 

 forest by cutting away ripe trees. As the reproduction proceeds, the 

 80193— Bull. 358—09 3 



