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PDFWood shrinks greatly in drying from the green to the oven-dry condition. (See Table XIV.) Consequently a block of wood measuring a cubic foot when green will measure considerably less when oven-dry. It follows that the density of oven-dry wood does not represent the weight of the dry wood substance in a cubic foot of green wood. In other words, it is not the weight of a cubic foot of green wood minus the weight of the water which it contains. Since the latter is often a more convenient figure to use and much easier to obtain than the weight of oven-dry wood, it is commonly expressed in tables of “specific gravity or density of dry wood.”
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----------------------| | TABLE XIV | |-----------------------------------------------------------
-----------------| | SPECIFIC GRAVITY, AND SHRINKAGE OF 51 AMERICAN WOODS | | (Forest Service Cir. 213) | |-----------------------------------------------------------
-----------------| | | | Specific gravity | Shrinkage from green to | | | Mois- | oven-dry, based on | oven-dry condition | | COMMON NAME | ture |--------------------+---------------------------| | OF SPECIES | content | Volume | Volume | In | | Tangen- | | | | when | when | volume | Radial | tial | | | | green | oven-dry | | | | |-----------------+---------+---------+----------+--------+-
-------+---------| | | Per | | | Per | Per | Per | | | cent | | | cent | cent | cent | | | | | | | | | | Hardwoods | | | | | | | | | | | | | | | | Ash, black | 77 | 0.466 | | | | | | white | 38 | .550 | 0.640 | 12.6 | 4.3 | 6.4 | | " | 47 | .516 | .590 | 11.7 | | | | Basswood | 110 | .315 | .374 | 14.5 | 6.2 | 8.4 | | Beech | 61 | .556 | .669 | 16.5 | 4.6 | 10.5 | | Birch, yellow | 72 | .545 | .661 | 17.0 | 7.9 | 9.0 | | Elm, rock | 46 | .578 | | | | | | slippery | 57 | .541 | .639 | 15.5 | 5.1 | 9.9 | | white | 66 | .430 | | | | | | Gum, red | 71 | .434 | | | | | | Hackberry | 50 | .504 | .576 | 14.0 | 4.2 | 8.9 | | Hickory, | | | | | | |
