R£;PRODUCTlON OP WESTERN YELLOW PINE 



281 



only the trees which are windfirm. This mean.s avoiding very tall 

 trees in excessively exposed situations and trees which before the cut- 

 ting were protected by neighbors which are to be removed. The sam- 

 ple-plot records show that windfall is confined almost entirely to yel- 

 low pine of the larger diameters. Since, however, the maximum loss 

 on any of the four plots was only 1.12 per cent of the yellow pine in 

 five years, a detailed analysis of the factors involved is not warranted 

 at the present time. When the records have been continued ten vears 

 they should begin to yield valuable data. 



Table 4. — Classification of Dead Trees, 1909-1914 



In tiic spring of 1917 unusual damage resulted from heavy snow at 

 Flagstaflf, .\rizona. Twenty-eight inches of wet snow fell .\i-)ril 17 

 and 18. Practically all of this adhered to the branches, with the result 

 that not only did branches break, but trees wiiit down. Since the 

 storm was unaccompanied by strong wind, tlu- i-lTect !■< attributed 

 mainly to the wciglit of snow. 



