154 THE PRINCIPLES OF HANDLING WOODLANDS 



by little or no undergrowth, and by a deep layer of litter 

 and humus. This forest floor is a very poor germina- 

 ting bed, and the first requisite for reproduction is to has- 

 ten the decomposition of the vegetable material. This is 

 accomplished by the preparatory cutting, which admits a 

 free circulation of the air. The object is to open up the 

 forest enough to bring about this rapid disintegration of 

 the humus, but not enough to allow the soil to run wild 

 with weeds and brush. 



2. A second object is to stimulate seed production. 

 The first thinnings admit more light to the crowns and 

 stimulate assimilation, and hence seed reproduction. 



3. Still another object is gradually to accustom the 

 trees to isolation, and make them more windfirm. 



These purposes may sometimes be accomplished by 

 making a single thinning. If, however, the forest is very 

 dense, it may be necessary, on account of danger from 

 windfall, to open up the forest gradually by two or, in 

 some cases, three thinnings. 



The preparatory cuttings are thinnings which open 

 the canopy uniformly throughout the stand. The trees 

 taken out in the preparatory cutting are primarily of the 

 following character: 



1. Trees infected with disease. 



2. Trees with suppressed, broken, or otherwise de- 

 fective crowns. 



3. Trees with overdeveloped, spreading crowns. 



4. Very tall, slender trees likely to be overthrown by 

 the wind. 



