318 
Growth. on the average acre, upland type—Growth per cent on 
the average acre of upland timber was roughly figured by Pressler’s 
formula, , 
V-v _ 200 
V+u aie ome 
where V equals the present volume on the average acre; and v, its volume 
n or ten years ago. The merchantable volume at present was computed 
as 635.53 cubic feet and by figuring from growth tables the volume of 
each diameter class ten years ago, the total volume at that time was found 
to be 477.68 cubic feet. Using the formula, we get 2.87 as the growth 
per cent. This can be applied like simple interest to the present stand, 
giving the annual increment on the average acre as 18.05 cubic feet, or 
about 1/5 of a cord per acre per annum. It would have been more exact 
to follow Recknagel’s method (Recknagel, 716) and to have found a 
growth per cent for each diameter class, applying this as a percentage to 
get the increment on the volume of that diameter class and totaling these 
increments, but according to Chapman (’21) it is not safe to apply such. 
a figure over large areas because the average age, thrift, or other condi- 
tions may differ widely from that of the sample area. If, however, this 
figure were applied to our 131,217 acres of upland merchantable timber 
it would give an annual increment of about 13,000,000 board feet, assum- 
ing that a cubic foot is equivalent to 5.5 board feet. 
Whether this growth of about 1/5 of a cord per acre per year for 
upland timber is correct or not, it indicates that the annual growth is very 
low owing to poor stocking, to fires, and to lack of thinning at proper 
intervals. Baker (’21) cites an example of oak in the sandy region of 
southern New Jersey where a thinned acre had increased in volume at the 
rate of about one cord per acre per annum, whereas a check plot near it, 
not thinned, had only increased 1.1 cords in seven years. An improve- 
ment cutting in a stand of 20-year-old mixed hardwoods in the same 
state resulted in a gain of 9.4 cords per acre in 10 years, or, again, almost 
a cord per acre per year. 
PHYSIOGRAPHIC FEATURES 
TOPOGRAPHY 
The area covered by this report may be divided for convenience into 
the Mississippi bottomlands and the interior highlands. The Mississippi 
bottomlands occupy about 18% of the total area of the 697,286 acres, with 
an average width of four and one-half miles. The relative width at two 
different places is shown on the Profiles sheet. This part of the area 
is cut by old river channels and is still subject to local overflows. Natural 
drainage is poor, the river having an average fall of only six or seven 
inches to the mile. 
