42 BULLETIN 544, TJ. S. DEPARTMENT OF AGRICULTURE. 
Having decided whether or not, during the period for which the 
future yield is to be forecasted, cutting will take place and in what 
amount, a volume growth table such as that outlined on page 41 
would be prepared. If a cutting is contemplated, there should be 
indicated on the stand table, as column 5, the average number of 
spruce trees of the different diameters which will be left for future 
growth. The present yield per acre of the stand would then be 
determined by multiplying the values in column 2 of the stand table 
by those in column 4 of the volume growth table. The future 
yield would similarly be determined by multiplying the values in 
column 5 of the stand table by those in columns 8, 9, 10, etc., of the 
growth table. 
The yield of second-growth stands may be arrived at in a manner 
similar to that just outlined. The more direct method, however, 
is to measure all the trees on sample areas in stands of typical devel- 
opment and known age. The height, diameter, volume, and all 
other data for each plot are determined separately; and these various 
data are finally combined into a table on the basis of the age of the 
trees and the site quality to which they belong. Such a table appears 
below for normally stocked second-growth stands measured in Maine, . 
New Hampshire, and Vermont. This table is based on data col- 
lected in unthinned stands of spruce which have come up on formerly 
cleared lands. So far as concerns the production of cubic volume 
and correspondingly, of cordwood volume, these values represent 
approximately the maximum for their respective ages and site classes. 
The table is thus suitable for use without modification in predicting 
the future yields of stands maintained for the production of pulpwood. 
