Question
What is the common moisture range in a single piece of lumber? I have heard of wet pockets in lumber. How common are these pockets? Often times I hear kiln operators say that a certain probe is reading high because it is in a wet pocket. Any info on this would be greatly appreciated.
Forum Responses
(Commercial Kiln Drying Forum)
From Gene Wengert, forum technical advisor:
The moisture range can be a few percent to 20 percent or more, depending on the species and the presence of bacteria (I am not counting injured wood.) The drier the wood, the smaller the variation tends to be. Wet pockets are not common in most species, but can be found in eastern white pine, hemlock, cottonwood, aspen, and some others, but would not be found in oak, maple, yellow-poplar, etc.
Regarding your comment about a few wet pieces, even a few high MC pieces after drying (not talking about wet pockets now) are not acceptable. All the (hardwood) lumber should be within 1.5% MC of the average, at the least, and even less variation is better. A mediocre hardwood lumber kiln load will have 95% of the pieces within 1.5% MC; a good drying job will have 95% of the pieces within 1/2% MC (or, as Contributor J says "0.5% MC").
Common Lumber Name | A | B | C |
Hardwoods | |||
Alder, Red | 9.9 | 19.2 | 2506 |
Apple | 10.9 | 31.7 | 4132 |
Ash, Black | 9.3 | 23.4 | 4132 |
Ash, Green | 14.3 | 27.6 | 3590 |
Aspen, Bigtooth | 10.3 | 18.7 | 2439 |
Aspen, Quaking | 10.3 | 18.2 | 2373 |
Basswood | 6.2 | 16.6 | 2174 |
Beech, American | 8.9 | 29.1 | 3793 |
Birch, Paper | 8.8 | 25.0 | 3260 |
Birch, Sweet | 11.9 | 31.2 | 4065 |
Birch, Yellow | 9.2 | 28.6 | 3723 |
Buckeye | 8.9 | 17.2 | 2235 |
Butternut | 11.3 | 18.7 | 2440 |
Cherry | 13.8 | 24.4 | 3184 |
Chesnut, American | 11.6 | 20.8 | 2708 |
Cottonwood | 8.5 | 16.1 | 2102 |
Dogwood | 6.8 | 33.3 | 4331 |
Elm, American | 10.2 | 23.9 | 3116 |
Elm, Rock | 12.2 | 29.6 | 3860 |
Elm, slippery | 11.5 | 25.0 | 3251 |
Hackberry | 11.8 | 25.5 | 3319 |
Hickory, Bitternut (Pecan) | 14.7 | 31.2 | 4062 |
Hickory (True) | |||
Hickory, Mockernut | 9.1 | 33.3 | 4332 |
Hickory, Pignut | 9.3 | 34.3 | 4332 |
Hickory, Shagbark | 10.9 | 33.3 | 4333 |
Hickory, Shellbark | 6.6 | 32.2 | 4195 |
Holly, American | 8.3 | 26.0 | 3387 |
Hophornbeam, Eastern | 7.9 | 32.8 | 4266 |
Laurel, California | 15.1 | 26.5 | 3456 |
Locust, Black | 21.2 | 34.3 | 4470 |
Madrone, Pacific | 7.8 | 30.2 | 3925 |
Maple (Soft) | |||
Maple, Bigleaf | 12.8 | 22.9 | 2980 |
Maple, Red | 13.1 | 25.5 | 3318 |
Maple, Silver | 12.4 | 22.9 | 2981 |
Maple (Hard) | |||
Maple, Black | 12.3 | 27.0 | 3523 |
Maple, Sugar | 12.3 | 29.1 | 3793 |
Oak (Red) | |||
Oak, Black | 11.7 | 29.1 | 3792 |
Oak, California black | 16.4 | 26.5 | 3455 |
Oak, Laurel | 6.3 | 29.1 | 3791 |
Oak, Northern red | 13.6 | 29.1 | 3793 |
Oak, Pin | 13.0 | 30.2 | 3928 |
Oak, Scarlet | 13.2 | 31.2 | 4065 |
Oak, Southern red | 9.6 | 27.0 | 3520 |
Oak, Water | 10.4 | 29.1 | 3793 |
Oak, Willow | 6.4 | 29.1 | 3790 |
Oak (White) | |||
Oak, Bur | 15.4 | 30.2 | 3928 |
Oak, Chestnut | 10.1 | 29.6 | 3858 |
Oak, Live | 17.5 | 41.6 | 5417 |
Oak, Overcup | 10.7 | 29.6 | 3860 |
Oak, Post | 11.0 | 31.2 | 4063 |
Oak, Swamp chestnut | 10.7 | 31.2 | 4063 |
Oak, White | 10.8 | 31.2 | 4062 |
Persimmon | 7.0 | 33.3 | 4332 |
Sweetgum | 8.9 | 23.9 | 3115 |
Sycamore | 10.7 | 23.9 | 3115 |
Tanoak | 9.0 | 30.2 | 3926 |
Tupelo, Black | 10.4 | 23.9 | 3116 |
Tupelo, Water | 12.4 | 23.9 | 3115 |
Walnut | 13.4 | 26.5 | 3454 |
Willow, Black | 8.6 | 18.7 | 2438 |
Yellow-poplar | 10.6 | 20.8 | 2708 |
Common Lumber Name | A | B | C |
Softwoods | |||
Baldcypress | 13.2 | 21.9 | 2844 |
Cedar, Alaska | 14.4 | 21.9 | 2844 |
Cedar, Atlantic white | 10.9 | 16.1 | 2100 |
Cedar, eastern red | 16.4 | 22.9 | 2981 |
Cedar, Incense | 13.1 | 18.2 | 2371 |
Cedar, Northern white | 11.1 | 15.1 | 1964 |
Cedar, Port-Orford | 12.6 | 20.2 | 2641 |
Cedar, Western red | 12.2 | 16.1 | 2100 |
Douglas-fir, Coast type | 12.3 | 23.4 | 3049 |
Douglas-fir, Interior west | 13.2 | 23.9 | 3116 |
Douglas-fir, Interior north | 14.0 | 23.4 | 3048 |
Fir, Balsam | 9.9 | 17.2 | 2236 |
Fir, California red | 10.6 | 18.7 | 2437 |
Fir, Grand | 10.7 | 18.2 | 2371 |
Fir, Noble | 10.1 | 19.2 | 2507 |
Fir, Pacific silver | 10.4 | 20.8 | 2711 |
Fir, Subalpine | 10.5 | 16.1 | 2101 |
Fir, White | 12.2 | 19.2 | 2506 |
Hemlock, Eastern | 12.6 | 19.8 | 2573 |
Hemlock, Western | 11.5 | 21.8 | 2847 |
Larch, Western | 11.3 | 25.0 | 3251 |
Pine, Eastern white | 12.3 | 17.7 | 2303 |
Pine, Lodgepole | 11.5 | 19.8 | 2576 |
Pine, Ponderosa | 12.6 | 19.8 | 2573 |
Pine, Red | 12.2 | 21.3 | 2777 |
Southern yellow group | |||
Pine, Loblolly | 12.9 | 24.4 | 3183 |
Pine, Longleaf | 15.0 | 28.1 | 3658 |
Pine, Shortleaf | 12.9 | 24.4 | 3183 |
Pine, Sugar | 12.6 | 17.7 | 2302 |
Pine, Western white | 10.0 | 18.2 | 2370 |
Redwood, Old growth | 14.9 | 19.8 | 2573 |
Redwood, Second growth | 13.2 | 17.7 | 2302 |
Spruce, Black | 11.3 | 19.8 | 2575 |
Spruce, Engelmann | 10.0 | 17.2 | 2234 |
Spruce, Red | 10.6 | 19.2 | 2506 |
Spruce, Sitka | 10.8 | 19.2 | 2506 |
Tamarack | 12.0 | 25.5 | 3318 |