60 THE ADIRONDACK SPRUCE 
purposes, but each acre is confined to a single situation and the 
possible number is so small, on account of the length of time re- 
quired to take them, that the general average is not as good as by 
the chain method. 
After the valuation surveys were completed in the 
field their results were worked out, with the object of 
finding the stand of Spruce on the area surveyed. To 
this end the average diameters and heights of the trees 
were first ascertained for each acre, then the general 
average was found for all the acres, first massed in 
groups and then all together, and finally the last result 
was used to get from the Volume Tables and the aver- 
age number of trees per acre the amount of standing 
timber on all the acres taken together. From this 
sum it was easy to find the average stand per acre. 
The average diameters and heights were calculated as follows: 
The average diameters were computed for all trees on each acre 
six inches and over in diameter, ten inches and over, twelve inches 
and over, and fourteen inches and over. The heights correspond- 
ing to these diameters were determined from the large number of 
height measurements which were taken throughout the Park in 
connection with the, valuation surveys. Eight hundred such 
measurements were made with a German instrument, Faustmann’s 
Spiegelhypsometer, and recorded in connection with the acres on 
which they were made. The height measurements for each group 
of acres were entered on cross-section paper, the diameters being 
laid off on the horizontal and the heights on the vertical lines, and 
a regular curve was drawn through the points which represented 
the measurements. From these curves the heights corresponding 
to the various diameters were found. 
For the purpose of working them up, the valuation 
surveys were grouped in two ways: First, according 
to the situation, under the heads of Swamp land, Spruce 
