I 

 INTRODUCTION 43 



where stands are established by artificial seeding, or 

 planting. The forester is apt to choose the species 

 which give promise of the highest returns, and to 

 establish pure stands of it. Then again, the seeding 

 or planting of a single species is simpler and often 

 cheaper than if two or more species are in mixture. 



There are, however, certain advantages in producing 

 mixed forests, and these should be considered when a 

 new stand is established. They are as follows: 



1. Mixed crops form a denser leaf-canopy, and hence 

 cast a heavier shade than pure stands. This is due to 

 the overlapping of the crowns of trees whose natural 

 crown development and ability to bear crowding differ. 



2. In a judicious mixture of species there are a lar- 

 ger number of trees than in pure stands. This is the 

 result of differences in ability to endure crowding, dif- 

 ferences in crown development, and differences in root 

 development. 



3. It has been actually demonstrated that a larger vol- 

 ume of product can be obtained in mixed than in pure 

 stands. 



4. Many species are less subject to damage from fire, 

 insects, disease, and windfall when in mixture than when 

 grown pure. 



5. By a judicious mixture certain trees develop a bet- 

 ter form, and hence higher quality of wood, than in pure 

 stand. 



6. Mixed stands have a higher esthetic value than 

 pure stands. 



