2 INTRODUCTION. 



influence the climate, to regulate the drainage of the 

 country, to prevent landslips or avalanches, to arrest 

 shifting sands, etc. 

 In each of these and other eases the particular species of 

 tree to be grown and the method of treatment are likely to 

 differ, and it is the business of the forester to select those 

 species and methods which realise the object of management 

 most fully and in the most economic manner. More especially, 

 the forester must always consider what effect the species and 

 the selected method of treatment are likely to have on the 

 property, and he must remember that any exceptional strain 

 put upon the soil for more than a limited period, in order to 

 realise an exceptional effect, must be followed by a corre- 

 sponding period of relaxation. Unless this is given, the soil, 

 in the majority of cases, will deteriorate, and it may ulti- 

 mately become absolutely sterile. Such an exceptional strain 

 may suit the special requirements of a particular owner, but 

 is not in the interest of the general community. Political 

 Economy teaches, that the correct mode of procedure points to 

 the careful preservation of the productive powers (or factors) 

 of any given locality, so as to render possible the production of 

 the same effect, or an increased one, regularly and indefinitely. 

 Experience has shown that in forestry the safest method of 

 preserving the productive powers of a locality consists in 

 maintaining uninterruptedly a crop of forest vegetation on the 

 area. The more frequently and the longer the ground is 

 uncovered and exposed to the full effects of sun and air 

 currents, the more, in the majority of cases, is the productive 

 power liable to be reduced. 



The subject of Sylviculture will be treated under the 

 following headings : — 



Part I. — The Foundations of Sylviculture. 



II. — Formation and Regeneration of Woods. 

 ,, III. — Tending of Woods. 



TV.— Sylvicultural Notes on British Forest Trees. 



