14 



A PRIMER OF FORESTRY. 



them will be full of knots, and its value will be small. 



If, on the other hand, the trees stand too closely 



together, although their 

 trunks will be tall and clear of 

 branches, they will be small 

 in diameter, and for that 

 reason low in value. With 

 the right amount of growing 

 space, trees grow both tall 

 and of good diameter, and 

 their trunks supply lumber 

 of higher price because it is 

 wide and clear. 



THE YIELD OF A FOREST. 



FIG. 6. A white cedar which has One of the central ideas of 



had too much growing space. ,, . , , , ,1 <, 



The tree is large, but full of knots, forestry is that the amount ot 

 Very little g d woo( * taken from an health 



forest and the amount grown 

 by it should be as nearly equal 

 as possible. If more grows than 

 is cut, then the forest will be 

 filled with overmature, decaying 

 trees; but if more wood is cut 

 than is grown, then the supply 

 of ripe trees will be exhausted, 

 and the value of the forest will 

 decline. To make the cut equal 

 to the growth does not mean 

 that the volume of wood grown 

 each year on every acre should be cut from that acre, 

 but that the total growth of all the acres, for one or 



FIG. 7. Old trees which have 

 had the right amount of 

 growing space to make 

 clean trunks and clear 

 lumber. Germany. 



