Bisbee daily review., 1915-01-03
Roughly Estimated One Pound of Coal is Equivalent To Two of Wood-Forest Laboratory Studying.
FEW HARD VARIETIES
 EQUAL COAL VALUE
Resinous Woods Have Great CT Heat Value Per Pound Than Non-Resinous-Much Variation Found in Tests.

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 lab oratory. which show also about how many cords of certain kinds of wood are required to obtain an amount Of heat equal to that in ton of coal
 Certain kinds of wood, such as hickory, oak. beech, birch. hard ma ple ash, elm, locust, longleaf 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
 It takes a cord and a half of short leaf pine, hemloek, 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, basswood. spruce and white pine
 Equal weights of dry, nonresinous woods however, are said Co nav, factically the same heat value regard Less of species, and as a consequence it can be stated as a general propcsi, ton that the heavier the wood the more heat to the cord Weight fo' weight, however, there is very little difference between various species. the average heat for all that have been calculated is 46OO calories, or heat units. per kilogram A kilogram of resin will develop 94OO heat units or about twice the average fa rOOd As consequence re .rnU5 Oods have greater heat value per pound than non-resluous woods, and this n- creased value varies, of course, wlCu the resin content.
 The available heat value of a cord of wood depends on many different factors It has a relation not only to the amount of resin it contains bu. to the amount of moisture present Fur thermore, cords vary as to tiie amount of sold 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 con siderable in cord made of twisted. crooked and knotty sticks Out of the 12S cubic feet, a fair averag of solid wood is about eighty cubic feet
 It is pointed out, however thN heat value is not the only test of use. fitness in fuel wood and since 95 pel cent Of all wood used for fuel is con sumed for domestic purposes, large ly in farm houses, such factors as rapidity of burning and ease of light ing 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 non-resinous woods, has the highest fuel value per unit volume of wood. and has other advantages. It 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 yalume, but has other adyant- ages. It ignites readily and gives out a quick, hot flame, but one that soon dies down. This makes it a favorite with rural housekeepers as summer wood. because it is particularly adapted for hot days in the kitchen.
 The fuel qualities of chestnut adapt it particularly to work in brass found ries, where it gives just the required amount of heat and it is therefore ln favor. Coastwise vessels in Florida pay twice as much for Florida button wood as for any other, because it turns with an even heat and mini mum amount of smoke and ash.
 The principal disadvantage of the reainous pines is their only back smoke.
 The placing Of Mclaughlin at the head of American tennis for the year