CHOICE OF SPECIES. 119 



of moisture and air currents must be carefully considered. 

 The soil and, if necessary, the subsoil as well must be 

 examined as to depth, degree of porosity and moisture, com- 

 position and admixture of humus. The development of any 

 trees already growing on the locality, or in its vicinity, should 

 be carefully studied. An investigation of this kind will 

 generally indicate what species are capable of thriving on a 

 locality ; it should, however, not be overlooked that any species 

 found growing naturally on the area are not always those best 

 adapted for it, because their presence may depend on circum- 

 stances other than a general suitability of soil and climate : 

 for instance, a shade bearing species may have ousted a light 

 demanding one, or a greater power of reproduction may have 

 enabled one species to drive out another possessed of less 

 energy in that respect. 



As long as the factors of the locality are fairly the same 

 over the whole area, the latter may be treated in a uniform 

 manner, but the occurrence of decided differences may 

 necessitate the selection of different species for difi'erent parts. 

 Any attempt at uniformity in spite of such differences may 

 lead to a serious loss in returns. 



In order to provide for a continuous preservation of the 

 fertility of the locality, it is necessary to select species which 

 give sufficient shelter to the soil and a good supply of humus, 

 or, at any rate, to mix such species in sufficient numbers with 

 those which do not shelter the soil. This rule can only be 

 disregarded in thoroughly favourable localities. Under these 

 circumstances, species with dense crowns must receive special 

 attention in making a selection for middling and inferior 

 localities ; in addition, interference with the fertility of the 

 soil, such as the removal of leaf mould, excessive grazing, 

 faulty treatment, etc., must be carefully avoided. Above all, 

 personal fancy on the part of the forester for a particular 

 species must be set aside. 



Not unfrequently several species are found to be equally well 

 adapted for a locality. In such cases other considerations 



