FORESTRY AND IRRIGATION 



July 



the timber has reached some size. In 

 the foregoing section it was shown that 

 such woods do best when thinned to 

 the C grade, which also yields a good 

 amount of merchantable wood. The 

 selection system, however, also shows 

 well, and as a paying result is the first 

 consideration for the average American 

 thinning, it will be wise to combine the 

 methods and cut the greatest amount 

 of timber compatible with the best final 

 yield. 



there are probably many cases where 

 woodlot owners are willing to make a 

 reasonable outlay. In twenty-year-old 

 growth or thereabouts, remove most of 

 Class II and take out those specimens 

 of Class \b and a which are noticeably 

 crowding the better members of the 

 same class. Cut all trees which have 

 started a few years before the others 

 and have grown up branch}' or badly 

 formed. If the mixture needs regula- 

 tion, this is the time to attempt it. 



BEFORE THINNING 



AFTER THINNING 



PROSPECTIVE MERCHANTABLE 

 STAND 



STANDING? 

 STANDING 



FROM CLASS I 

 FROM CLASS H 



THINNING IN ay-YEAR-oLD PLANTED WHITE PINE. 



Every woodlot has different condi- 

 tions, but there are a few general points 

 which may be discussed in broad lines 

 and which are applicable to all. True 

 thinnings are only possible in stands 

 of fairly thrifty growth which have a 

 good cover. Ragged and sparse woods 

 must be built up by improvement cut- 

 tings, which are not here considered. 



A. Thinning a Sapling Stand. 

 There are not many places where it 

 would pay to thin in young forests, but 



The cover should not be broken more 

 than temporarily. 



B. Thinning in Pole Stands. If thrifty 

 forest has got well into the pole stage 

 without a thinning, there will be con- 

 siderable wood for removal. Select 

 particularly thrifty, well-formed trees 

 from Class la and set them free to a 

 reasonable extent on all sides by re- 

 moving any class which presses them. 

 Bring the remaining members of \a 

 and b into a good relative position by 



