RE.MEASUREMENT Of SAMPLE PLOTS 835 



7. Total volume per average acre (board feet) 



1910 1915 1920 1910 1915 1920 

 Average of all three plots 37,461 43,757 47,899 8,870 9,812 10,216 



Thus this G4-year-old stand contains (on the basis of close utiliza- 

 tion and no discount for defect and breakage in logging) close to 50,000 

 board feet per acre, or over 10,000 cubic feet per acre. 



8. Annual groivth of firs nozv living 



Cubic feet Board feet 



1910-1915 1915-1920 1910-1915 1915-1920 



Plot 1 163.06 131.46 1123.2 1138.0 



Plot 2 183.30 38.96 1191.2 602.0 



Plot 3 218.90 72.11 1463.3 745.0 



Average 188.44 80.84 1259.2 828.0 



The above shows that the current increment has fallen oflf both in 

 cubic feet and in board feet on all plots except Plot 1, w^here the board- 

 feet growth is larger the last half decade than before. This is partly- 

 due to the extraordinary loss shown in No. 5 above. Assuming that 

 these windfalls were still standing and alive, the increment during the 

 period 1915-1920 would have been as follows: 



Cubic feet Board feet 



Plot 1 156.08 1191.0 



Plot 2 97.60 813.0 



Plot 3 99.51 832.0 



Average 117.73 945.0 



This windfall loss does not account for all the decrease in increment. 

 It may be normal for a stand of this age when the struggle for ex- 

 istence is so keen and the loss from suppression has been so great. Mr. 

 Hanzlik's normal volume table for Site I Douglas fir plots shows a 

 slump in growth at about this period. It can hardly be attributed to 

 unfavorable climatic factors for the weather records show at a nearby 

 station a greater precipitation for 1915 to 1920 than in the preceding 

 five years. It is noticeable that the board-foot growth, but not the 

 cubic-foot growth (which includes the small trees many of which are 

 dying off), on Plot 1 is greater than in the first half decade. This is 

 the lightest stocked plot and No. 3 above shows that the trees on this 

 plot have made the most rapid growth. This would su])]iort the con- 

 tention that the falling off in both cubic-foot and hoard-foot growth 



