IMPEOVEMENT THINNING. 



I. INTRODUCTION. 



By improvement thinning is meant the systematic removal 

 of a portion of the trees in a growing crop of timber to 

 benefit the portion that remains. Improvement thinning 

 is the principal means which the forester has at his disposal 

 of influencing the development of a stand of forest trees. 

 The farmer and the gardener have their distinctive methods 

 of cultivation, by which they increase the yield and im- 

 prove the quality of their crops. The forester cannot use 

 the methods of the farmer and the gardener in growing 

 crops of timber trees. The great expense of such methods, 

 the different nature of the crop, and the rough and stony 

 character of many forest soils, make a different and less 

 expensive form of cultural treatment necessary, that is, 

 improvement thinning. 



Improvement thinning is a very important part of forestry 

 for us to consider here in Massachusetts for the coming 

 quarter of a century. A great many people think that 

 treeplanting is all there is to forestry. It is true that tree- 

 planting is an important part of forest work. There are 

 considerable areas of practically waste land in the Com- 

 monwealth that ought to be planted to forest trees, and it 

 is economically sinful to allow them to lie idle when they 

 might be producing something of value. But, while this is 

 true, it is also true that the improvement of forests that al- 

 ready exist is just as important as the creation of new ones 

 by planting. According to the estimate made by the United 

 States Geological Survey, fifty-two per cent of the area of 

 the Commonwealth is already covered with a growth of forest 

 trees. It would seem that, if more emphasis ought to be 

 placed on one branch of work than on another, it should be 

 placed on increasing the productivity of our large forest area, 

 rather than upon an extension of that area. 



