The Ely miner. [volume] (Ely, Minn.) 1895-1986, 1915-01-01
The Fuel Value Of Wood

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 seras
vice laboratory, which show also
about how many cords of certain
kinds of wood are required to
obtain an amount of heat equal t6]
that in ton of coal.
Certain kinds of wood, such as
hickory. oak, beech, birch, hard
maple, ash, elm, locust, longleaf
pine, and cherry, have fairly high
heat values. and only one cord of
seasoned wood of these species Isl
required to equal one ton Of good
coal. 81
It takes cord and half of
shortleaf pine. hemlock, red gum.
Douglas fir, sycamore, and soft
maple to equal a ton of coal, and
two cords of cedar, redwood,
poplar, catalpa, Norway pine.
cypress, Eastwood, spruce, and
white pine.
Equal weights of dry, nom
resinous woods, however, are said
to have practically the same heat
value regardless of species, and as
a 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 average heat
for all that have been calculated is
800 calories, or heat units, per
kilogram. A kilogram of resin
will develop 9,4OO heat units, or
twice the average for wood. AS a
consequence. resinous woods have
greater heat value per pound
than non-resinous woods, and this
increased value varies, of course,
with the resin content.
The available neat value of a
cord of wood depends on many
different factors. 1t has a relation
not only to the amount of resin it
contains but to the amount OF
moisture present. Furthermore,
cords vary as to the amount of solid
wood they contain, even when they
are of the standard dimension and
occupy 12S cubic feet of space.
A certain proportion of this space
is made up of air spaces between
the sticks, and this air space may
be considerable in a cord made of
twisted, crooked, and knotty sticks.
Out of the 12S cubic feet, fair
average of solid wood is about so
cubic feet.
1t is pointed out, however, that
heat value is not the only test OF
usefulness in fuel wood and since
o5 per cent of all wood used for
fuel is consumed for domestic pur-
poses, largely in farm houses, such
! factors as rapidity of burning and
ease of lighting are important.
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 resinous
woods, has 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, fol
lowed by beech, birch, and maple
). Pine has a relatively low heat
value per unit volume, but ha:
!; other advantages. 1t ignite:
readily and gives out quick hot
. flame, but one that soon dies down
This makes it favorite with rura
!. housekeepers as summer wood
becauae it is particularly adapted
for hot days in the kitchen.
, The fuel qualities of chestnu
adapt it particularly to work II
brass foundries, where it gives jus
t the required amount of heat and i
is therefore in favor. Coastwis'
vessels in Florida pay twice a
: much for Florida buttonwood a
: for any other, because it burn
: with an even heat and with
minimum amount of smoke ant
+ ash.
J, The principal disadvantage O
the resinous pines is their oil
: black smoke.