THE USE OF WOOD FOR FUEL. 33 
one factory which normally used 50 tons of soft coal a day used for 
a month in mid-winter a minimum of 15 tons of coal and 50 cords 
of mixed hardwood daily, from which the conclusion may be drawn 
that for steam production 1 cord of green hardwood is equal to 
seven-tenths of a ton of soft coal. Careful tests made in Georgia 
showed that to keep a room at a comfortable temperature with an 
open-hearth fireplace nearly 10 times as much wood must be con- 
sumed as when a stove is used. This plainly indicates that it is very 
uneconomical to depend on open fireplaces alone for heating houses. 
WOOD FUEL FOR THE FUTURE. 
GROWING TIMBER FOR FUEL. 
There is probably a general impression that timber for firewood 
can be grown rather rapidly, within a period of 5 to 10 years. This 
will not hold true for general forest areas,, especially hardwoods. 
From 20 to 50 years and even longer are required to produce a full 
stand. The sprout forests of southern New England will grow a 
crop of wood in 10 or 15 years and perhaps less; a full stand, how- 
ever, requires more time. Planted catalpa on good soil will yield 
fairly well in 8 or 10 years; and eucalyptus or blue gum will produce 
a heavy growth in five or six years. Willow and cottonwood on 
suitable sites will yield firewood in from 10 to 15 years, but usually 
a longer time is required for large yields even with these rapidly 
growing species. Old field and white pine make rapid growth and 
yield heavily in a comparatively short time. With hardwoods like 
oak, hickory, maple, beech, birch, etc., not much can be expected in 
less than from 30 to 50 years. 
An average of 1 cord of fuel wood per acre per annum is a large 
yield, taking the country as a whole. Hardwood forests will prob- 
ably not average more than three-fourths of a cord growth per year 
and many will not make more than one-fourth of a cord. With the 
faster-growing species 2 cords per acre is a high average annual yield 
even on favorable sites. With average natural stands of cottonwood, 
cordwood can be obtained in about 16 years, with a total yield of 
approximately 424 cords per acre, or an annual yield of 2.7 cords. 
Under particularly favorable conditions of growth the time may be 
shortened to 12 years, especially where thinning and cultivation are 
possible. Since stands cut for cordwood can be most easily renewed 
by coppicing, the second rotation should be much shorter than the 
first because of the more rapid growth of the sprouts. Eucalyptus 
in California is reported to yield as high as 7 cords per acre per an- 
num on a comparatively short rotation. With the pines a yield of 
over 4 cords per acre per annum has been reached. Only on the best 
