Practical Sylviculture 



137 



of good trees. Work carried on in the woodlot in caring 

 for the crop of trees is known by the general term of thin- 

 ning. Thinning 

 may mean ac- 

 tual removal of 

 good trees 

 when the stand 

 is too thick, 

 thr removal of 

 live, poor 

 and worthless 

 trees or the re- 

 moval of any- 

 t h i n g that 

 tends to im- 

 prove the tree 

 growth. The 

 practice of in- 

 telligent thin- 

 ning very 

 quickly shows 

 a marked 

 on the develop- 

 ment of the 

 trees in a 

 stand. In 

 Kurope during 

 a period of 74 

 years, the for- 

 ests have yielded an increase in wood of 300 percent, or 

 from an annual growth of 20 cubic feet to the acre a year 



Fio. 37. A Rood example of woodlot of the seleo- 



timi t ,,f nil ;IK,. S| Ixitlirom!' 



hard woods. 



