A Windfall Problem 323 



between 50" and 60" — except for the cedar type, where the 

 greatest is between 40" and 50". In windfall on the other hand, 

 for the area and for each type, both by volume and by number 

 of trees, the greatest amount is from 30" to 40." The amount of 

 windfall both by standing trees and by volume, for trees between 

 32" and 40" varies, approximate figures for standing trees being, 

 in the fir type 40 per cent, in the hemlock type 25 per cent, and in 

 the cedar type and also for the whole area 35 per cent; and by 

 volume, 15 per cent for the fir type, 20 for the hemlock type, 40 

 for the cedar type, and 35 per cent for the area. 



All the figures for the per cent of the total volume that is in 

 windfall, with the exception of those for the fir type, show es- 

 sentially the same thing, as is brought in graphic form by the 

 accompanying curves, No. 2. There is a rise up to 32" to 40" 

 and then a rather rapid descent continuing from 70" to 80", after 

 which there is a rapid ascent. On the total 331.6 acres on which 

 the data were obtained, there was no windfall in the trees above 

 100" in d. b. h. This indicates that after this diameter is reached, 

 the trees are so firmly established that the danger from wind- 

 fall is at a minimum. In the fir type, cedar above 60" appears 

 immune from windfall ; the same conditions appear in this type 

 as in the whole area, except that the lowest per cent before the 

 second rise is for from 42" to 50" instead of from 72" to 80". 

 Although above 60" d. b. h. no windfall in cedar occurred, 26 

 per cent of the stand by volume, and over 5 per cent by number 

 of trees, is between 60" and 100". The greatest amount of wind- 

 fall both by volume and by number of trees occurs in trees from 

 30" to 40" d. b. h. and after that the danger of windfall is much 

 less until the trees are from 80" to 100", when it is again 

 considerable. 



As a result of the study, it appears that the greatest amount of 

 windfall occurred in the hemlock type, where the soil was poorer, 

 and where surface fires had run through the stand. In the 

 cedar windfall the amount by volume was 12 per cent, whereas 

 in other types it was only 8 per cent. For areas where the con- 

 ditions are very similar to those on this watershed in regard to 

 general forest conditions, and approximately the same relative 

 amounts of the associated species, about 10 per cent of the mer- 

 chantable cedar will be windfall. The greater per cent of it will 

 be in trees from 30" to 40" in diameter. In general, trees over 



