NOTES 305 



central Idaho, the object of which was to determine the effect of 

 thinning and pruning on diameter growth of western yellow pine. The 

 stand consisted of a dense growth of seedlings and saplings. Diameter 

 measurements were taken with a steel tape at 4^^ feet above the 

 ground on 30 medium sized saplings, ranging from 2 to 7 inches in 

 diameter breast high and averaging approximately 18 feet in height, on 

 3 areas which were treated as follows : 



Area i. Thinned by cutting out about one-half of the saplings, 

 leaving the remaining trees standing from 2 to 8 feet apart, the average 

 distance being about 6 feet. All diseased, defective, and suppressed 

 saplings were removed. The saplings left standing were pruned to 

 a height of about 8 feet. 



Area 2. This area was thinned as in Area 1, but the standing trees 

 were not pruned. The trees left standing were from 2 to 10 feet 

 apart, the average distance being from 6 to 7 feet. 



Area 5. This area was left in its natural condition to serve as a 

 check on the other two areas. 



The same trees were remeasured in June, 1918, seven years later. 

 Since no height measurements were secured at the time the plots were 

 established no information is available on height growth or increment. 

 The data on diameter growth are summarized as follows : 



Average d.b.h., 1918. . 

 Average d.b.h., 1911. . 

 Periodic growth for 7 



years 



Periodic annual growth 



It is evident that the removal of the diseased, defective, and sup- 

 pressed trees from a western yellow pine stand results in an increase 

 in the rate of diameter growth of the remaining trees. The response 

 to an increase in the amount of growing space is more pronounced 

 in the younger age classes. 



C. F. K. 



Black Walnut in Utah 



Black walnut was planted in Utah as early as 1866. George Ritter. 

 living 43/j miles southwest of Ogden, had as a part of the load which 



