Wood 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."
|----------------------------------------------------------------------------| | 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, | | | | | | | | big shellbark | 64 | .601 | | 17.6 | 7.4 | 11.2 | | " " | 55 | .666 | | 20.9 | 7.9 | 14.2 | | bitternut | 65 | .624 | | | | | | mockernut | 64 | .606 | | 16.5 | 6.9 | 10.4 | | " | 57 | .662 | | 18.9 | 8.4 | 11.4 | | " | 48 | .666 | | | | | | nutmeg | 76 | .558 | | | | | | pignut | 59 | .627 | | 15.0 | 5.6 | 9.8 | | " | 54 | .667 | | 15.3 | 6.3 | 9.5 | | " | 55 | .667 | | 16.9 | 6.8 | 10.9 | | " | 52 | .667 | | 21.2 | 8.5 | 13.8 | | shagbark | 65 | .608 | | 16.0 | 6.5 | 10.2 | | " | 58 | .646 | | 18.4 | 7.9 | 11.4 | | " | 64 | .617 | | | | | | " | 60 | .653 | | 15.5 | 6.5 | 9.7 | | water | 74 | .630 | | | | | | Locust, honey | 53 | .695 | .759 | 8.6 | | | | Maple, red | 69 | .512 | | | | | | sugar | 57 | .546 | .643 | 14.3 | 4.9 | 9.1 | | " | 56 | .577 | | | | | | Oak, post | 64 | .590 | .732 | 16.0 | 5.7 | 10.6 | | red | 80 | .568 | .660 | 13.1 | 3.7 | 8.3 | | swamp white | 74 | .637 | .792 | 17.7 | 5.5 | 10.6 | | tanbark | 88 | .585 | | | | | | white | 58 | .594 | .704 | 15.8 | 6.2 | 8.3 | | " | 62 | .603 | .696 | 14.3 | 4.9 | 9.0 | | " | 78 | .600 | .708 | 16.0 | 4.8 | 9.2 | | yellow | 77 | .573 | .669 | 14.2 | 4.5 | 9.7 | | " | 80 | .550 | | | | | | Osage orange | 31 | .761 | .838 | 8.9 | | | | Sycamore | 81 | .454 | .526 | 13.5 | 5.0 | 7.3 | | Tupelo | 121 | .475 | .545 | 12.4 | 4.4 | 7.9 | |----------------------------------------------------------------------------|