The Washington times. [volume] (Washington [D.C.]) 1902-1939, 1914-12-26
HEAT UNITS IN WOOD
HALF THOSE IN COAL
Forest Service Laboratory De-
termines Relative Values for
Use as Fuel.

The fuel value of two pounds OF wood
is roughly equivalent TO that of one
pound of coal This is given as the
result OF certain calculations now being
made in the Forest Service laboratory.
which show also about how many
cords of certain kinds of wood are re-
quired to obtain an amount Of heat
equal to that in a ton OF coal.
Certain kinds of wood, such as hick-
ory, oak, beech, birch, hard maple, ash,
elm. locust, longlcaf pine. and cherry.
have fairly high heat values, and only
one cord of seasoned wood of these
species is required TO equal one ton OF
good coal.
1t takes a cord and half of shortleaf
pine, hemlock. red gum. Douglas fir,
sycamore. and soft maple to equal a
redwood. poplar. catalpa, Norway pine,
cypress, Eastwood, spruce. and white
pine,
Weight Guide To Value.
Equal weights of dry, non-resinous
tically the same heat value regardless
Of species, and. as q consequence. it can
be stated as a general proposition that
the heavier the wood the more heat to
the cord. Weight for weight. however.
there is very little difference between
various species: the aveUage heat for
all that have been calculated is 400
calories. or heat units. per kiloGram.
a kilogram of resin will develop g.
100 heat units. or about twice the aver
age for wood. As a consequence. resin
o'ls woods have a greater heat value
Per pound than non-resinous woods, and
this increased value varies. of course,
with the resin content.
The available heat value of n cord of
wood depends on many different fac
tors. II has a relation not only TO the
amount of resin 1t contains but to the
amount of moisture present. Further
more. cords vary as to the amount of
solid wood hey contain, even when
they are of the standard dimension and
occupy Is cubic feet of space. A Ger
tain proportion of this space Is made
w of air spaces between the sticks,
and this air space may be considerable
I'm a cord made OF twisted, crooked, and
knotty sticks. Out OF the is cubic feet,
fair average OF solid wood is about
eighty cubic feet.
Heat Content Not Only Test.
1t is pointed out. however. that heat
value is not the only test Of usefulness
IN fuel wood and since 30 per cent of
all wood used for fuel is consumed for
domestic purposes, largely in farm
houses, such factors as rapidity Of
Dortant. Each section of the country
has its favored woods and these are
said to be. in general, the right ones
to use. Hickory. OF the non-resinous
woods, mas the highest fuel value per
unit volume of wood, and has other
advantages. 1t burns evenly. and, as
housewives say. holds the heat
The oaks come next, followed by
beech. birch. and maple. Pine has a
relatively low heat value per unit vol
ume. but has other advantages. II
ignites readily and gives out a quick
hot fame but one that soon dies down.
This makes il a favoritc with rural
housekeepers as a summer wood. be-
cause It Is particularly adapted for hot
days in the X tchens
The fuel qualities of chestnut adapt
il particularly TO work Ia. brass found
lies. where it gives just the required
amount OF heat and it Is therefore In
favor. Coastwise vessels in F]oridu
pay twice rs much for Florida button
wood as for any other. because It
burns with an even heat and with q
minimum amount of smoke and ash.
The principal disadvantage of the
rcsinous pines ia their oily black smoke.