Table 2. --Mean growth and shoot-blight infection data for potential crop trees in 

 western hemlock regeneration, Thomas Bay, Alaska 



Total Dead Disease Terminal 



Area Height branching branching index 1 kil led 2 



------- Meters -------- Percent 



1 2.96 398.1 36.2 0.091 a 63.2 



2 2.64 224.6 31.7 .141 b 80.0 

 3 3 2.81 326.0 61.0 .187 c 75.0 

 4 k 4.16 680.0 54.9 .081 42.0 



i Means followed by a different letter are significantly different (p=0.05; 

 Duncan Multiple Range Test) . Area No. 4 not included in analyses. 

 Accumulative for 1971-1976. 



3 Fertilized May 1969; 464 kg Agricultural Grade urea/hectare. 

 ^Thinned in 1975 to 2.4 x 2.4 m spacing. 



Thinned area. --Thinning was accomplished only 15 months prior to the disease sur- 

 vey. Therefore, comparisons between the thinned and unthinned areas must be conditioned. 

 The average potential crop tree was larger on the thinned area than on the unthinned 

 areas (table 2) because it was 4 years older and largest trees were selected as crop 

 trees. Disease index and percentage terminal kill were lower than on the unthinned 

 areas (table 2) because severely infected trees were removed during the thinning. 

 These data indicate good quality control in the selection of crop trees during the 

 thinning operation. The ratio of Sitka spruce to western hemlock is higher in the 

 thinned than in the unthinned areas. This was intended since Sitka spruce was favored 

 in leave tree selection. 



Fertilized vs. nonfertilized areas . - -The fertilized area had the lowest overall 

 stocking of the unthinned areas (table 1). However, the number of potential crop trees 

 was much higher than on the nonfertilized areas. Percentage dead trees in the sup- 

 pressed and intermediate crown classes was twice that of the nonfertilized areas. 

 Percentage top-kill trees in these crown classes was intermediate between the two non- 

 fertilized areas. Disease index for potential crop trees on the fertilized area was 

 the highest of all areas examined (table 2). 



7 



