THE fuel value of two pounds of wood is roughly equiv- 

 alent to that of one pound of coal. This is given as the 

 result of certain calculations now being made in the for- 

 est service laboratory, which show also about how many cords 

 of certain kinds of wood are required to obtain an amount of 

 heat equal to that in a 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 is required to equal one ton of good coal. 



It takes a cord and a 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, basswood, spruce, and white pine. 



Equal weights of dry, non-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 propopsi- 

 tion that the heavier the wood the more heat to the cord. 

 Weight for weight, however, there is very little difference be- 

 tween various species; the average heat for all that have been 

 calculatd is 4,600 calories, or heat units, per kilogram. A kilo- 

 gram of resin will develop 9,400 heat units, or about twice the 

 average for wood. As a consequence, resinous 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 a cord of wood depends on many 

 different factors. It has a relation not only to the amount of 

 resin it contains but to the amount of moisture present. Fur- 

 thermore, cords vary as to the amount of solid wood they con- 

 tain, even when they are of the standard dimension and oc- 

 cupy 128 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 128 cubic feet, a fair average of 



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