28 



TIMBER. 



piece with very narrow rings is light. On the other hand, the weight 

 of a piece of hard maple or birch is quite independent of the width of 

 its rings. 



The bases of limbs (knots) are usually heavy, very heavy in conifers, 

 and also the wood which surrounds them, but generally the wood of the 

 limbs is lighter than that of the stem, and the wood of the roots is the 

 lightest. 



In general, it may be said that none of the native woods in common 

 use in this country are, when dry, as heavy as water, i. e., G2 pounds to 

 the cubic foot. Few exceed 50 pounds, while most of them fall below 40 

 pounds, and much of the pine and other coniferous wood weighs less 

 than 30 pounds per cubic foot. 



The weight of the wood is, in itself, an important quality. Weight 

 assists in distinguishing maple from poplar. Lightness, coupled with 

 great strength and stiffness, recommends wood for a thousand different 

 uses. To a large extent weight predicates the strength of the wood, 

 at least in the same species, so that a heavy piece of oak will exceed in 

 strength a light piece of the same species, and in pine it appears prob- 

 able that, weight for weight, the strength of the wood of various pines 

 is nearly equal. 



Weight of kiln-dried tvood of different sjyecies. 



(a) Very heavy woods : 



Hickory, oak, persimmon, osage orange, black locust, hackberry 



blue beech, best of elm, and ash 



(6) Heavy woods : 



Ash, elm. cherry, birch, maple, beech, walnut, sour gum, coffee 

 tree, honey locust, best of Southern pine, and tamarack 



(c) V\ oods of medium weight: 



Southern pine, pitch pine, tamarack, Douglas spruce, western 

 hemlock, sweet gum, soft maple, sycamore, sassafras, mul- 

 berry, light grades of birch and cherry 



(d) Light woods : 



Norway and bull pine, red cedar, cypress, hemlock, the heavier 

 spruce and fir, redwood, basswood, chestnut, butternut, tulip, 

 catalpa, buckeye, heavier grades of poplar 



(e) Very light woods: 



White pine, spruce, fir, white cedar, poplar 



Approximate. 



Specific 

 weight. 



Weight of— 



0. 70-0. 80 

 . 60- . 70 



. 50- . 60 



.40- .50 

 . 30- . 40 



1 cubic 

 foot. 



Pounds. 

 42-48 



36-42 



30-36 



24-30 

 18-24 



1,000 feet 

 of lum- 

 ber. 



Pounds. 

 3,700 



3,200 



2,700 



2,200 

 1,800 



For scientific names see list, p. 72. 



Since ordinary lumber contains knots and also more water than is 

 here assumed, and also since its dimensions either exceed or fall short 

 of perfect measurement, the figures in the table are only approximate. 



Thus, 1,000 feet, B. M., of longleaf pine weighs: 



Pounds. 

 Rough and green 4 500 



Boards, rough but seasoned 3' ^qq 



Boards, dressed and seasoned 3' qqq 



Flooring, matched, dressed and seasoned 2 500 



Weatherboarding beveled and dressed 1 5 qq 



