THE RED SPRUCE. 
59 
to an abnormal diameter development as well as of board-foot con- 
tents and a less-than-norrnal cubic and cord volume. The full effect 
of understocking is obviously obscured by the better-than-average 
height development of plot 17, which amounts to more than 10 feet 
above the average and would occasion a 12 to 15 per cent increase in 
volume. The subnormal total basal area is the best index in this 
case. As is to be expected, the overstocked stand, plot 39, shows a 
maximum cubic and cord volume. Plot 46 illustrates very well the 
benefits to be derived from a slight understocking such as would be 
4o 
so 
A -Plot -3S &yed £3yrs. 
3—P/ot <46 ayed €7 yr§. 
C = P/of/7 aped 6Syr$. 
C? 
60 
Fig. 3.— Effect of stocking on yield. Comparison of actual measurements of sample plots approximately 
65 years old, with the average measurements for a 65-year-old stand in the second grovcth yield table. 
All stands Quality II and measurements are for dominant (including codominant) and intermediate 
trees only. Plottings are in percentages of the normal or average values of the different factors. 
brought about by thinning. Thus, with a normal height growth a 
13 per cent understocking was accompanied in this instance by 
increases of 8 per cent in basal area, 12 per cent in average diameter, 
16 per cent in board-foot yield, 9 per cent in cubic-foot yield, an 11 
per cent in cordwood yield. 
BRUSH DISPOSAL. 
One of the mosi} potent sources of danger to spruce forests in general 
is the brush and, more particularly, the lops or branch wood which 
litter the ground after logging. The culled logs and tops from which 
the branches have been lopped do not of themselves constitute a 
