. SYSTEMS OF CLEAR-CUTTING 121 



cannot help interfering to some extent with the de- 

 velopment of some of the young trees. About 10 

 or 20 per cent, of the area will be shaded from above, 

 and this proportion of the new crop will be prevented 

 from making normal growth. In case of loblollv pine, 

 this would result in reducing the yield from the new 

 crop by about from 1,000 to 2,000 board feet. On the 

 other hand, if 20 of the reserves lived through the 

 second rotation successfully, they alone would vield at 

 least from 5,000 to 10,000 feet of lumber of the highest 

 grade. 



Application. — There are no instances in this country 

 of the systematic use of this system. In Europe, the 

 plan of reserving certain trees for growth over a second 

 rotation has long been in practise. The purpose of these 

 reserves has, however, been chiefly for growth. Re- 

 production has generally been accomplished by planting. 



The system may well be applied to many even-aged, 

 comparatively young stands in this country, such as lob- 

 lolly and other yellow pines in the South, white pine 

 occasionally, Western yellow pine, and Douglas fir. 



Clear-Cutting in Two or More Operations. — The con- 

 dition requiring the clear-cutting of an area in one opera- 

 tion is temporary. The advance in values will before 

 long permit the cutting in a single operation of a smaller 

 amount in a given logging unit than is now practicable. 

 Already in many stands that require clear-cutting, it is 

 possible to restrict the first cuttings to strips or patches 

 occupying not over 40 or 50 per cent, of the area, and 



