4 
mum temperature is not less than 24° F., can be purchased for about 
$30 per acre. 
The cost of preparing an acre of ground for planting does not 
ordinarily exceed $6. Seedlings can be purchased for $6 per thou- 
sand. The planting of 1,000 trees (enough for an acre) costs about 
$4. The cost of cultivating and caring for a plantation for two years 
does not usually exceed $7 per acre, including the purchase of trees 
to fill blanks in the plantation. Any thinnings made up to the time 
of the first cutting should pay for themselves. The cost of establish- 
ing a plantation and carrying it through the first two years, excluding 
the cost of land, is therefore about $23 per acre. 
Taxes on the class of land used for growing blue gum amount to 
about 30 cents per acre per year. Ten cents per acre per year should 
be expended in protection from fire. These two items represent a 
fixed annual charge per acre for the 10-year period before the first 
cutting. Discounted at 4 per cent, this amounts to a present invest- 
ment of about $3.25 per acre.t The total investment involved in 
establishing 1 acre of plantation is, therefore, about $56.25. 
YIELDS OF PLANTATIONS. 
Actual measurements show that an average annual yield of about 
6.4 standard cords, or 8.5 California cords, per acre is produced by 
the best blue-gum groves in the State.2 This figure was obtained 
by finding the mean annual growth per acre of all the groves exam- 
ined in 1910 which contained over 5 standard cords, and then de- 
termining the average of 20 per cent of the groves showing the 
most rapid mean annual growth.* It was thus based upon the best 
5 of the 25 groves examined. While not strictly accurate, since 
the rate of growth of trees varies somewhat at different ages, it is 
sufficiently so for practical purposes in this instance, where the 
range in ages is not great. Individual groves have occasionally done 
better. One grove was found which produced 185.9 standard cords 
in 25 years, or about 7.4 cords per year. Another produced over 59 
cords in nine years, or nearly 6.6 cords per year. On the other hand, 
three groves under average conditions, with fair soil and the water 
1This is derived from the formula Pas the present value of an amount spent an- 
r (1.0 ps—1) 
~ (0 pax. op.)’ 
charges for taxes and protection; r—annual tax and protection charge ($0.40) ; p=rate 
of interest (4 per cent); and "number of years (10). The present value of the 
charges for taxes and protection is the amount which, invested at the given rate of 
interest, will meet these charges annually, and will be exhausted at the end of the 
period. 
2A standard cord contains 128 cubic feet of stacked wood, or approximately 90 cable 
feet of solid wood; a California cord, the local unit, is three-fourths of a standard cord 
and consequently contains 96 cubic feet of stacked wood, or approximately 67.5 cubic 
feet of solid wood. 
8 Bulletin 1, California State Board of Forestry, pp. 12—14. 
nually for a given number of years, in which E==present value of the 
