+) 
table not more than 25 feet from the surface, show an annual growth 
per acre of only 4.05, 3.9, and 3.7 cords, respectively. Under unfav- 
orable conditions, with a deep water table or with hardpan near 
the surface, the annual growth in two cases has been as low as 1.6 
cords and 1.1 cords per acre. An annual yield of 6.4 cords per acre, 
or 64 cords per acre in 10 years, may therefore be accepted as a fair 
estimate of what may be obtained upon the best sites under the 
methods of management heretofore used. 
Assuming a stumpage price of $2.50 per standard cord, this yield 
would return $160 in 10 years from the wood alone. This represents 
nearly 13 per cent compound interest on the original investment of 
$56.25. Out of that amount $30, the cost of the land, may be con- 
sidered as restored to the investor with the harvesting of the crop, 
and is in effect an additional return. 
Since blue gum sprouts rapidly, the same return of 64 cords, worth 
$160, should be obtained periodically at the end of every 10 years for 
at least several rotations. In this case, however, no additional ex- 
penditure is necessary for establishing or caring for the plantation. 
The amount invested is, therefore, $33.25 ($30 for land and $3.25 for 
capitalized taxes and protection). A return of slightly more than 
19 per cent would thus be realized in growing each of the sprout crops 
. following the first, or planted crop. This is assuming that the value 
of the land remains unchanged and that this amount is reinvested 
periodically after each crop is harvested. 
In the figures just given it is assumed also that the operation is 
handled by the individual investor on an area large enough to be ~ 
managed economically. This should be not less than 50 acres. 
The greatest yield of any blue-gum grove measured by the Forest 
Service was found in a plantation 32 years old. This stand contains 
57,820 board feet of timber per acre, measured by the Scribner Deci- 
mal C log rule, besides 30.9 standard cords (41.2 California cords) of 
wood to be cut from tops too small for lumber. Assuming a stump- 
age rate of $5 per thousand feet for lumber and $2.50 per standard 
cord, the return on this grove would amount to $366.35 per acre for 
the 32-year period. If it costs $60.15 per acre (on the same basis as 
that used above) to buy and plant the land, care for the young trees 
two years, and pay taxes and protection charges 32 years (discounted 
to the present at 4 per cent), the return is a little over 6 per cent com- 
1This is derived from the well-known valuation formula Y=—(C+E)X1.op2+§ 
(1.op8?—1), in which Y=yield at end of rotation ($160) ; C=cost of establishing and 
earing for plantation ($23) ; E=capitalized expenses for taxes and protection ($3.25) ; 
S=cost of land ($30); ®=length of rotation (10 years); and p=rate of interest. 
The —1 in the formula is due to the fact that the value of the land at the end of the 
rotation is assumed to be the same as at the beginning, so that interest alone is lost on 
the money invested in land. 
