STUDY OF WINDFALL LOSS 619 



Table 2. — Occurrence of i<'iiidfall by half decades foUozinng cutting. 



Half decades after cutting 0-5 6-10 11-15 16-20 21-25 26-30 



Plot I — ^20 acres — 20 years since cutting. 



Number of trees thrown. 

 Per cent oy volume 



28 

 54 



12 

 30 



1 



11 



Plot II — 40 acres — 15 years since cutting. 



Plot III — 20 acres — 27 years since cutting. 



Number of trees thrown. 

 Per cent by volume 



1 



21 



The interesting point brought out by Table 2 is that, of all the trees 

 that are vvindthrown over a long period of years, a strikingly large 

 proportion — often as much as two-thirds or more — is blown down in 

 the first five or six years immediately following cutting. The re- 

 mainder is thrown in rapidly decreasing proportions year by year until 

 about twenty years after cutting when the loss for a five-year period 

 becomes but o or -i per cent of the total volume thrown. In the actual 

 case of Plot I, 54 per cent of the volume of the entire windfall loss for 

 twenty years occurred in the first half-decade after cutting, and but 

 one tree fell in the fourth half-decade — a 30-inch tree which would 

 not have fallen had the area been under management, because so big a 

 tree would not have been left standing. On Plot II, 94 per cent of the 

 loss for fifteen years occurred in the first five-year period and only 

 2 per cent in the third five-year period. The same preponderant per- 

 centage in the first half-decade holds true for the other plots, except 



