GENERAL CONSIDERATIONS 81 



stand and that, as a result, growth is not so well maintained as 

 where the trees differ more or less in age and are not composed of 

 a single species, as is the case in most forests that arise from 

 natural seeding. It is also believed by many that a tree growing 

 on the site where the seed germinates develops a better and more 

 natural root system. Where natural regeneration is possible the 

 trend of present-day forestry in Europe is away from pure stands 

 and artificial regeneration toward mixed stands and natural seed- 

 ing. Throughout Prussia beech is being brought back into Scotch 

 pine stands. In Saxony where spruce has been planted in pure 

 stands for successive generations, a change is now being made 

 toward natural regeneration and mixed stands. It is believed by 

 many that the repetition of the same species, rotation after rota- 

 tion, ultimately exhausts the soil. 



5. ADVANTAGES AND DISADVANTAGES IN ARTIFICIAL 

 REGENERATION 



The following are the most important advantages and disad- 

 vantages in artificial regeneration: 



a. Artificial regeneration is independent of the local occurrence 

 of seed years, since seed may be brought in from outside regions 

 or stored from the excess crops of previous years. A previously 

 determined area can be regenerated each year, while in natural 

 regeneration this is not possible because of the intermittent nature 

 of seed years. This is a decided advantage as it affects the 

 equalization of the yield, the handling of labor, and the manage- 

 ment of operations. 



b. Artificial regeneration enables the forester to develop a sim- 

 pler and more definite plan for the management of the forest. 



c. Artificial regeneration, particularly on open land, exposes 

 the young plants to greater danger from frost, drought, fire, 

 weeds, and insects. This danger is so great with tender species 

 that the regeneration must be made under a shelterwood. 



d. The clear-cutting of large areas prior to artificial regeneration 

 exposes the soil to adverse climatic conditions which may seri- 

 ously affect its fertility. 



e. In artificial regeneration, particularly planting, there is usually 

 a smaller number of plants per acre than in natural seeding. As a 

 consequence, the trees are likely to be more branchy except where 

 the planting is very dense. 



