CHAPTER III 



THE CHOICE OF SPECIES IN ARTIFICIAL 

 REGENERATION (Continued) 



1. THE EVALUATION OF THE SITE FACTORS 



IT is the duty of the forester to determine the trees that are 

 best adapted for growth in any particular locality. As the site 

 factors measure the quality or yield capacity of the locality, 

 methods must be developed by which they can be readily ascer- 

 tained. The quality of the site must be known in order to avoid 

 growing a species that has no chance of thriving upon it. The task 

 is an extremely difficult one because the effects of some of the 

 factors of the site on tree growth are as yet imperfectly understood. 

 The climatic factors are of special importance; hence, careful con- 

 sideration should be given to the effect of geographical position, 

 altitude, aspect, gradient, and air currents upon temperature and 

 atmospheric moisture. Special attention should also be given to 

 the soil and subsoil. The soil should be examined in particular as 

 to depth, porosity, moisture, and composition. The methods for 

 determining site quality are as follows: 



a. Direct method, i.e., determining site quality or yield ca- 

 pacity by the measurement of the several factors of the site. 



b. Indirect method : 



1. Determining site quality or yield capacity from the crop 

 of trees. 



2. Determining site quality or yield capacity from the her- 

 baceous or shrubby vegetation. 



2. The Evaluation of the Site Factors by the Direct Method 



In recent years foresters and botanists have given much at- 

 tention to methods for measuring the site factors and relating the 

 vegetation to them. Thus, Trauseau l has attempted to correlate 



1 Trauseau, E. N.: Climatic factors and centers of plant distribution. 

 (Mich. Acad. Sci., 7th report, pp. 73-75. 1905.) 



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