68 THE ADIRONDACK SPRUCE 
Tables 15 and 16 give the results of the 1046 valua- 
tion surveys classified according to situation. The 
following tables (19-22) show the average diameters, 
heights, number of trees, and yield per acre of the 1046 
valuation surveys classified according to the yield per 
acre of Spruce ten inches and over in diameter. 
The average diameters and heights were determined, as is fully 
explained on page 60, by averaging the values found for the indi- 
vidual valuation surveys. The number of trees per acre was 
determined directly from Table 18, which gives the average num- 
ber of trees per acre of each inch in diameter. The method 
described on page 60 was used to compute the yield per acre. 
It was first determined for trees fourteen inches and over in diam- 
eter by multiplying the number of trees by the value in the 
Volume Tables corresponding to the average diameter and height. 
The contents of trees twelve and thirteen inches in diameter, ten 
and eleven, and six to nine inches, were computed and added to 
that found for trees over fourteen inches, and the total contents of 
all trees six inches and over was found by addition. 
