834 JOURNAL OF FORESTRY 



S. Diameter of average Douglas fir tree (inches) 



igio 1915 1920 



Plot 1 13.30 14.29 16.00 



Plot 2 13.51 14.60 16.20 



Plot 3 14.27 15.62 16.70 



Average 13.69 14.84 16.30 



The diameter growth of the surviving trees during the last five-year 

 period has been shghtly greater than in the preceding period; that is, 

 the diameter growth of the average tree was 1.15 inches from 1910 to 

 1915 and 1.46 inches from 1915 to 1930. 



4. Total basal urea of living Douglas firs (square feet) 

 igio 1915 1920 



Plot 1 180.601 195.568 207.260 



Plot 2 212.260 229.740 230.910 



Plot 3 207.455 229.195 234.820 



Average 200.100 218.170 224.330 



This table shows an increase in the gross basal area of the living 

 trees in spite of the loss of so many trees by death, but the rate of 

 increase is very much less in the last half decade than in the preceding. 



5. Extraordinary loss from tvind and snozv damage, 1915-1920 



No. of trees Cu. ft. vol. Bd. ft. vol. 



Plot 1 4 123.10 266.0 



Plot 2 9 293.20 1056.0 



Plot 3 4 137.00 435.0 



Average 5 2/3 184.43 585.7 



Of all the loss by volume in the last five-year period, 42 per cent 

 of the total was due to extraordinary windfall and snow breakage and 

 58 to suppression. 



6. Ratio of several crown classes on average acre (percentages) 



Dofuijiant Intermediate Suppressed 



1910 25 57 18 



1915 17 55 28 



1920 18 56 26 



As Stated above, differentiation of crown classes is not positive due 

 to the element of personal judgment, but if this table is taken at its 

 face value it indicates an increased number of suppressed trees and 

 consequent increased crowding. This is borne out by the greater loss 

 of trees by suppression and the lessened growth in the last half decade. 



