INTRODUCTION y 



which it will be impossible to establish a stand by natural 

 reproduction in less than a century. This represents the 

 worst conditions of forest destruction. But even where 

 fire has not played so important a part, but where lum- 

 bering has been conducted in the usual way, reproduction 

 is generally slow and meager. This means loss of growth. 

 To the owner it means that the soil is idle for a long 

 time, and that the period between removing the timber 

 and the maturing of the new crop is much longer 

 than is necessary. To the country at large it means a 

 great loss which, in the aggregate for a single State, may 

 amount to millions of dollars each year. 



Desirable Species. — Nature does not discriminate 

 against the inferior species. In the struggle for existence 

 between two species, the one which has the least market 

 value often wins. In any forest left to nature a great 

 deal of ground is occupied by trees which do not have as 

 high technical value as some others. This is particularly 

 true in a country like America, where the number of 

 species is large. Thus, in southern New England the 

 ground is often occupied by birch, soft maple, ironwood, 

 or other species of relatively little value, where chestnut 

 and oak might be growing. Lumbering and fire are often 

 followed by a deterioration of the soil and a growth of 

 species inferior to those in the original stand. The pur- 

 pose of silviculture is to improve the composition of the 

 forest, so that a given area will be occupied by the most 

 valuable species which are capable of growing under the 

 given conditions. 



