i86 



INTERMEDIATE CUTTINGS THINNINGS 



rule to be broken only in special cases, where the owner is 

 willing to invest the cost of the thinning and where the ultimate 

 financial benefits of the operation are clearly discernible. 



As soon as the openings made by the preceding thinning 

 have closed a second cutting should be made. The interval 

 between cuttings may vary from 3 to 10 years, or even 



10ft.- 



18 feet 



h 



.2 1 



Cut clear 



in Second 



Thinning 



FIG. 76. 



Same stand as in Fig. 75, but 10 years later after a second strip thinning has 

 been made. The strips in this case were cut at right angles to the first strips. 

 The timber left (shown by cross-hatching) is in the form of compact groups. 

 The trees on the edges have opportunty for increased growth, but the trees 

 standing in the center of the groups have not been benefited. 



longer in exceptional cases, depending primarily upon the 

 severity of the thinning, the quality of the site and the in- 

 herent ability of the species to take advantage of the in- 

 creased opportunity for growth. (See Figs. 68 and 77.) 



On a good site thinnings can be repeated frequently, and 

 each thinning may be relatively heavy because of the rapidity 



