If a species is not footnoted with a number (1-18), then the specific gravity for that species has not been verified by Wagner. In most cases, with unverified species, these species have the same botanical name as the verified version but just a different common name. Many species (botanical name) in the world have many different common names. The footnote descriptions are shown at the bottom of the page.*
Wood Species Types in Alphabetical Order
To obtain the most accurate moisture content measurements with your Wagner moisture meter, you must set the meter for the correct species settings value for the species you are going to measure. For our customers' convenience, we have calibrated our meter's species settings in terms of specific gravity.*
For those instances where you need to measure moisture in a wood species that is not shown in your User’s Manual, Wagner has compiled this extensive database of wood species with their associated specific gravity values.
The sources for our database include the United States Department of Agriculture, Forest Products Laboratory.
The published specific gravity values are the average for each species. There can and will be some variability of the specific gravity (density) within any species of wood, but the average specific gravity value (again, from the most valid published sources) will provide the best settings for your Wagner moisture meter.
Common Name | Botanical Name | Specific Gravity | Verified |
---|---|---|---|
Ta Lo | Schima wallichii | 0.62 | |
Tabaak | Anisoptera costata | 0.52 | |
Tabaak | Anisoptera curtisii | 0.52 | |
Tabaca | Pseudosamanea guachapele | 0.58 | |
Tabari | Couratari pulchra | 0.53 | 4 |
Prioria copaifera | 0.42 | ||
Cedrela odorata | 0.39 | ||
Swietenia macrophylla | 0.47 | ||
Tabebuia | Tabebuia serratifolia | 0.99 | 4 |
Prioria copaifera | 0.42 | ||
Populus balsamifera | 0.34 | ||
Populus balsamifera | 0.34 | ||
Pterocarpus soyauxii | 0.64 | ||
Tadiri | Planchonella euphlebia | 0.89 | |
Pinus taeda | 0.51 | ||
Tahua | Tabebuia serratifolia | 0.99 | 4 |
Tahuari | Tabebuia serratifolia | 0.99 | 4 |
Tahungan | Heritiera javanica | 0.65 | |
Diospyros ebenum | 0.94 | ||
Tairak | Anisoptera costata | 0.52 | |
Taire | Anisoptera costata | 0.52 | |
Tairi | Anisoptera costata | 0.52 | |
Prioria copaifera | 0.42 | ||
Takhian | Hopea odorata | 0.63 | |
Takhian Chan | Balanocarpus heimii | 0.78 | |
Takhian Chan Ta Maeo | Balanocarpus heimii | 0.78 | |
Takhian Thong | Hopea odorata | 0.63 | |
Takhian Tong | Hopea odorata | 0.63 | |
Takhian Yai | Hopea odorata | 0.63 | |
Takhian-Tong | Hopea odorata | 0.63 | |
Takian | Hopea odorata | 0.63 | |
Takian-Chan | Balanocarpus heimii | 0.78 | |
Takien | Hopea odorata | 0.63 | |
Takien Chan | Balanocarpus heimii | 0.78 | |
Takloban | Erythrophloeum densiflorum | 0.68 | |
Taknian Chan Tamaeo | Balanocarpus heimii | 0.78 | |
Shorea negrosensis | 0.59 | ||
Takram | Garuga pinnata | 0.51 | |
Shorea negrosensis | 0.59 | ||
Pometia pinnata | 0.60 | ||
Pterocarpus soyauxii | 0.64 | ||
Pometia pinnata | 0.60 | ||
Tala | Planchonella euphlebia | 0.89 | |
Tala Kiriya | Excoecaria agallocha | 0.42 | |
Pometia pinnata | 0.60 | ||
Talegotbon | Pygeum turnerianum | 0.44 | |
Taligaan | Koordersiodendron pinnatum | 0.71 | |
Talipugud | Alangium meyeri | 0.56 | |
Tall Albizzia | Albizia procera | 0.55 | |
Talu-Talu | Diplodiscus paniculatus | 0.62 | |
Tamad | Eschweilera sagotiana | 0.90 | |
Tamaga | Melia azedarach | 0.51 | |
Tamak | Mitragyna parvifolia | 0.59 | |
Tamanou | Calophyllum inophyllum | 0.55 | |
Tamanou | Calophyllum tomentosum | 0.59 | |
Tamarack | Larix decidua | 0.48 | 14 |
Tamarack | Larix laricina | 0.53 | 1 |
Larix occidentalis | 0.52 | ||
Pinus contorta | 0.41 | ||
Tamarotan | Terminalia amazonia | 0.76 | |
Tamaya | Melia azedarach | 0.51 | |
Tambolau | Myristica buchneriana | 0.41 | |
Tambolau | Myristica chartacea | 0.48 | |
Tambolau | Myristica hypargyraea | 0.44 | |
Tambolau | Myristica sp. | 0.54 | |
Enterolobium cyclocarpum | 0.35 | ||
Tamo | Fraxinus mandshurica | 0.63 | |
Shorea negrosensis | 0.59 | ||
Shorea negrosensis | 0.59 | ||
Tampipio | Couratari pulchra | 0.53 | 4 |
Tampudau | Anisoptera costata | 0.52 | |
Tampurau | Anisoptera costata | 0.52 | |
Tabebuia serratifolia | 0.99 | ||
Pometia pinnata | 0.60 | ||
Tananeo | Peltogyne porphyrocardia | 0.69 | |
Tananeo | Peltogyne venosa | 0.69 | |
Tang Hon | Calophyllum inophyllum | 0.55 | |
Tang Hon | Calophyllum tomentosum | 0.59 | |
Tanganyika Nuss | Aningeria altissima | 0.42 | |
Tanganyika Nuss | Aningeria dombeyi | 0.39 | |
Tanganyika Nuss | Aningeria robusta | 0.42 | |
Tanggaris | Koompassia malaccensis | 0.76 | |
Tangid | Canangium odoratum | 0.28 | |
Tangig | Canangium odoratum | 0.28 | |
Tangile | Shorea negrosensis | 0.59 | 4 |
Tangit | Canangium odoratum | 0.28 | |
Ta-Nich | Manilkara zapota | 0.71 | |
Tanimbuca | Terminalia amazonica | 0.76 | |
Tanoak | Lithocarpus densiflorus | 0.64 | 2 |
Taoub | Mezilaurus navalium | 0.79 | |
Tapal | Byrsonima coriacea | 0.68 | |
Tapana | Hieronyma alchorneoides | 0.58 | |
Tapanare | Hieronyma alchorneoides | 0.58 | |
Tapang | Koompassia excelsa | 0.75 | |
Taparai | Cordia alliodora | 0.51 | |
Tapgam | Diplodiscus paniculatus | 0.62 | |
Tapinhoa | Mezilaurus navalium | 0.79 | |
Tapsava | Virola koschnyi | 0.51 | |
Tapulan | Pinus merkusii | 0.59 | |
Tapulau | Pinus merkusii | 0.59 | |
Tarahuilca | Piptadeniastrum africanum | 0.63 | |
Taraka Vepa | Melia azedarach | 0.51 | |
Tariti | Intsia bijuga | 0.65 | |
Tarroeha | Hyeronyma laxiflora | 0.58 | |
Tarroema | Hyeronyma laxiflora | 0.58 | |
Taruma | Vitex cofassus | 0.67 | |
Platymiscium pinnatum | 0.87 | ||
Tashiro-Mame | Intsia bijuga | 0.65 | |
Tasmanian Blackwood | Acacia melanoxylon | 0.54 | |
Eucalyptus obliqua | 0.68 | ||
Tatajuba | Bagassa guianensis | 0.72 | 3 |
Tat Talun | Intsia palembanica | 0.65 | |
Plathymenia reticulata | 0.56 | ||
Plathymenia reticulata | 0.56 | ||
Tato-O | Vitex cofassus | 0.67 | |
Tat-Talun | Intsia bijuga | 0.65 | |
Tat-Talun | Intsia palembanica | 0.65 | |
Tauari | Couratari guianensis | 0.53 | 3 |
Tauari | Couratari pulchra | 0.53 | 4 |
Tauari | Couratari spp. | 0.53 | 3 |
Tauary | Couratari pulchra | 0.53 | 4 |
Tabebuia serratifolia | 0.99 | ||
Taun | Pometia pinnata | 0.60 | 4 |
Taun | Pometia tomentosa | 0.59 | |
Pometia pinnata | 0.60 | ||
Taung Thayet | Swintonia sp. | 0.62 | |
Nyssa sylvatica | 0.50 | ||
Taungsagaing | Tarrietia sylvatica | 0.82 | |
Tava | Pometia pinnata | 0.60 | 4 |
Tawa | Beilschmiedia tawa | 0.62 | 3 |
Pometia pinnata | 0.60 | ||
Tawa | Pometia spp. | 0.58 | 3 |
Pometia pinnata | 0.60 | ||
Tawtama | Cedrela toona | 0.47 | |
Tayaw | Excoecaria agallocha | 0.42 | |
Tabebuia serratifolia | 0.99 | ||
Tabebuia serratifolia | 0.99 | ||
Tayung | Diospyros mindanaensis | 0.78 | 14 |
Tchibudimbu | Oxystigma oxyphyllum | 0.53 | |
Tchikuebi | Bridelia aubrevillei | 0.59 | |
Tchissakata | Drypetes gossweileri | 0.63 | |
Tchitola | Oxystigma oxyphyllum | 0.53 | |
Teak | Chlorophora excelsa | 0.70 | |
Teak | Tectona grandis | 0.57 | 2 |
Teen Nok | Vitex parviflora | 0.68 | |
Teen-Nok | Vitex cofassus | 0.67 | |
Tein | Mitragyna parvifolia | 0.59 | |
Teinthe | Mitragyna parvifolia | 0.59 | |
Telat | Intsia bijuga | 0.65 | |
Tel-Kekuna | Aleurites moluccana | 0.14 | |
Tellamadi | Terminalia arjuna | 0.71 | |
Tema | Chlorophora excelsa | 0.70 | |
Hymenaea courbaril | 0.83 | ||
Temru | Diospyros celebica | 0.90 | 13 |
Tenam | Anisoptera costata | 0.52 | |
Tendu | Diospyros celebica | 0.90 | 13 |
Diospyros ebenum | 0.94 | ||
Tendu | Diospyros melanoxylon | 0.67 | |
Tenduet | Pygeum africanum | 0.61 | |
Tenek | Antiaris toxicaria | 0.35 | |
Tenetuet | Pygeum africanum | 0.61 | |
Pometia pinnata | 0.60 | ||
Tenu | Aleurites moluccana | 0.14 | |
Platymiscium pinnatum | 0.87 | ||
Teralin | Heritiera javanica | 0.65 | |
Teraling | Heritiera javanica | 0.65 | |
Terap | Artocarpus hirsuta | 0.52 | |
Terbulan | Endospermum macrophyllum | 0.41 | |
Terentang | Campnosperma brevipetiolata | 0.33 | |
Terepit | Tetramerista glabra | 0.73 | |
Tereticornis Gum | Eucalyptus tereticornis | 0.82 | |
Tete Congo | Eschweilera sagotiana | 0.90 | |
Hura crepitans | 0.40 | ||
Tewogboye | Terminalia ivorensis | 0.54 | |
Pinus palustris | 0.59 | ||
Th | Podocarpus neriifolia | 0.48 | |
Thabyegin | Syzygium buettnerianum | 0.73 | |
Thai-a-Dou | Grewia elastica | 0.63 | |
Thamaya | Melia azedarach | 0.51 | |
Thayet | Mangifera altissima | 0.52 | |
Thayet | Mangifera indica | 0.53 | |
Thayet Thitsi | Melanorrhoea spp. | 0.75 | |
The Eye-Blinding Plant | Excoecaria agallocha | 0.42 | |
Thilla | Excoecaria agallocha | 0.42 | |
Thingab | Hopea odorata | 0.63 | |
Thingan | Hopea iriana | 0.80 | |
Thingan | Hopea odorata | 0.63 | |
Thingan Byu | Hopea odorata | 0.63 | |
Thingan Net | Hopea odorata | 0.63 | |
Thingan Wa | Hopea odorata | 0.63 | |
Thinsingan | Hopea odorata | 0.63 | |
Thinwin | Millettia pendula | 0.87 | |
Thite | Castanopsis acuminatissima | 0.56 | |
Thitkado | Cedrela huberi | 0.40 | 4 |
Thitkado | Cedrela toona | 0.47 | |
Thitsi | Melanorrhoea spp. | 0.75 | |
Pterocarpus angolensis | 0.59 | ||
Pterocarpus angolensis | 0.59 | ||
Thong | Campnosperma brevipetiolata | 0.33 | |
Thong | Hopea odorata | 0.63 | |
Thong Mu | Pinus merkusii | 0.59 | |
Thongbeng | Koompassia malaccensis | 0.76 | |
Thongbueng | Koompassia malaccensis | 0.76 | |
Pterocarpus angolensis | 0.59 | ||
Thorny-Locust | Gleditsia triacanthos | 0.62 | |
Thort | Intsia bijuga | 0.65 | |
Thou | Artocarpus hirsuta | 0.52 | |
Tiaca-Ia | Manilkara zapota | 0.71 | |
Tiaong | Shorea negrosensis | 0.59 | 4 |
Astronium graveolens | 0.89 | ||
Astronium graveolens | 0.80 | ||
Picea sitchensis | 0.40 | ||
Taxodium distichum | 0.46 | ||
Tiga | Tristania decorticata | 1.03 | |
Pometia pinnata | 0.60 | ||
Tigerwood | Astronium graveolens | 0.89 | 19 |
Tigerwood | Astronium graveolens | 0.80 | 19 |
Tilai | Excoecaria agallocha | 0.42 | |
Tilautaea | Terminalia amazonia | 0.76 | |
Tilautaea | Terminalia arjuna | 0.71 | |
Tilautaea | Terminalia ivorensis | 0.54 | |
Tilautaea | Terminalia procera | 0.54 | |
Tileul d'Afrique | Mitragyna stipulosa | 0.53 | |
Tilleul | Tilia vulgaris | 0.51 | 13 |
Tilokoenoeroe | Hyeronyma laxiflora | 0.58 | |
Prioria copaifera | 0.42 | ||
Timbruni | Diospyros celebica | 0.90 | 13 |
Timmi | Chlorophora regia | 0.59 | |
Tinadan | Tristania decorticata | 1.03 | |
Tingkih | Aleurites moluccana | 0.14 | |
Tingyu | Pinus merkusii | 0.59 | |
Tinshu | Pinus insularis | 0.50 | |
Tinshu | Pinus merkusii | 0.59 | |
Tintin | Vochysia ferruginea | 0.52 | |
Tintin | Vochysia guianensis | 0.52 | |
Tinyu | Casuarina equisetifolia | 0.87 | |
Tinyu | Pinus insularis | 0.50 | |
Tinyu | Pinus merkusii | 0.59 | |
Cedrela odorata | 0.39 | ||
Pterocarpus soyauxii | 0.64 | ||
Tjemara | Casuarina equisetifolia | 0.87 | |
Tjengal | Balanocarpus heimii | 0.78 | |
Tjengal | Hopea odorata | 0.63 | |
Tntie budimbu | Oxystigma oxyphyllum | 0.53 | |
Tntubudimbu | Oxystigma oxyphyllum | 0.53 | |
Prunus serotina | 0.50 | ||
Taxodium distichum | 0.46 | ||
To | Piptadeniastrum africanum | 0.63 | |
Tobou | Mitragyna ciliata | 0.52 | |
Juglans cinerea | 0.38 | ||
Juglans nigra | 0.55 | ||
Todu | Cedrela toona | 0.47 | |
Toealang Ajam | Koompassia malaccensis | 0.76 | |
Toemaling | Koompassia malaccensis | 0.76 | |
Toemboes | Campnosperma brevipetiolata | 0.33 | |
Pometia pinnata | 0.60 | ||
Tohn | Campnosperma brevipetiolata | 0.33 | |
Tola | Beilschmiedia mannii | 0.62 | |
Tola Chimfuta | Oxystigma oxyphyllum | 0.53 | |
Tola Mafula | Oxystigma oxyphyllum | 0.53 | |
Tola Mafuta | Oxystigma oxyphyllum | 0.53 | |
Tola Noir | Oxystigma oxyphyllum | 0.53 | |
Tola Walnut | Oxystigma oxyphyllum | 0.53 | |
Tolong | Agathis borneensis | 0.41 | |
Tolong | Agathis philippinensis | 0.33 | |
Tom | Piptadeniastrum africanum | 0.63 | |
Tomboiro Noir | Chlorophora regia | 0.59 | |
Tonca Bean | Dipteryx odorata | 0.82 | |
Tong | Campnosperma brevipetiolata | 0.33 | |
Tonka | Dipteryx odorata | 0.82 | |
Tonka Gaiae | Dipteryx odorata | 0.82 | |
Tonkebean | Dipteryx odorata | 0.82 | |
Tonquin Bean | Dipteryx odorata | 0.82 | |
Toon | Cedrela huberi | 0.40 | 4 |
Toon | Cedrela toona | 0.47 | |
Toona | Cedrela toona | 0.47 | |
Tooti | Morus alba | 0.60 | |
Pinus taeda | 0.51 | ||
Torito | Hieronyma alchorneoides | 0.58 | |
Torn | Albizia procera | 0.55 | |
Torore | Mora excelsa | 0.89 | |
Tos | Intsia bijuga | 0.65 | |
Toubaouate | Didelotia brevipaniculata | 0.54 | |
Toum | Piptadeniastrum africanum | 0.63 | |
Toumbohiro Noir | Chlorophora excelsa | 0.70 | |
Touwe | Didelotia brevipaniculata | 0.54 | |
Terminalia superba | 0.40 | ||
Train | Syzygium buettnerianum | 0.73 | |
Pterocarpus angolensis | 0.59 | ||
Hymenaea courbaril | 0.83 | ||
Trayung | Diospyros ebenaster | 0.61 | 4 |
Trayung | Diospyros inclusa | 0.70 | 14 |
Trayung | Diospyros melanoxylon | 0.67 | |
Trayung | Diospyros pyrrhocarpa | 0.69 | 14 |
Platymiscium pinnatum | 0.87 | ||
Amburana cearensis | 0.58 | ||
Platymiscium pinnatum | 0.87 | ||
Platymiscium pinnatum | 0.87 | ||
Populus tremuloides | 0.38 | ||
Prioria copaifera | 0.42 | ||
Trementino Azucarero | Tetragastris altissima | 0.74 | |
Cedrela odorata | 0.39 | ||
Trompilio | Hieronyma alchorneoides | 0.58 | |
Trompillo | Hieronyma alchorneoides | 0.58 | |
Trompillo | Hyeronyma laxiflora | 0.58 | |
Hura crepitans | 0.40 | ||
Cedrela odorata | 0.39 | ||
Juglans cinerea | 0.38 | ||
Juglans nigra | 0.55 | ||
Buxus sempervirens | 0.83 | ||
True Cedar | Cedrus libani | 0.53 | 13 |
True Mahogany | Swietenia macrophylla | 0.47 | 2 |
Truong | Pometia pinnata | 0.60 | 4 |
Truong | Pometia tomentosa | 0.59 | |
Tsangu | Antiaris toxicaria | 0.35 | |
Tschikue | Bridelia aubrevillei | 0.59 | |
Tseekado | Cedrela toona | 0.47 | |
Tshabi | Musanga cecropioides | 0.23 | |
Tshibudimbu Tshikunze | Oxystigma oxyphyllum | 0.53 | |
Tshikalakala | Millettia laurentii | 0.81 | 14 |
Tshilombela | Musanga cecropioides | 0.23 | |
Tshilombelombe | Musanga cecropioides | 0.23 | |
Tshilungu | Mammea africana | 0.69 | |
Hymenaea courbaril | 0.83 | ||
Tualang | Koompassia excelsa | 0.75 | |
Tuamis | Intsia bijuga | 0.65 | |
Tuba | Oxystigma oxyphyllum | 0.53 | |
Tucang-Calao | Aglaia gigantea | 0.54 | |
Pometia pinnata | 0.60 | ||
Tuggan-Tuggan | Grevillea robusta | 0.54 | |
Tuhidia | Terminalia ivorensis | 0.54 | |
Tuhidya | Terminalia ivorensis | 0.54 | |
Tukam | Anisoptera costata | 0.52 | |
Diospyros ebenum | 0.94 | ||
Tul | Morus alba | 0.60 | |
Tule | Chlorophora excelsa | 0.70 | |
Tule Mufala | Chlorophora excelsa | 0.70 | |
Tule Mufala | Chlorophora regia | 0.59 | |
Liriodendron tulipifera | 0.42 | ||
Tulipan Africano | Spathodea campanulata | 0.25 | |
Liriodendron tulipifera | 0.42 | ||
Tulipwood | Dalbergia frutescens | 1.02 | 17 |
Liriodendron tulipifera | 0.42 | ||
Tulklu | Morus alba | 0.60 | |
Tulo | Alphitonia philippinensis | 0.35 | |
Tulpenboom | Spathodea campanulata | 0.25 | |
Tumaling | Koompassia malaccensis | 0.76 | |
Diospyros ebenum | 0.94 | ||
Diospyros ebenum | 0.94 | ||
Pometia pinnata | 0.60 | ||
Tundu | Cedrela toona | 0.47 | |
Tungururiet | Pygeum africanum | 0.61 | |
Tuni | Cedrela toona | 0.47 | |
Tunki | Diospyros celebica | 0.90 | 13 |
Tunt | Morus alba | 0.60 | |
Tuntri | Morus alba | 0.60 | |
Nyssa aquatica | 0.50 | ||
Nyssa sylvatica | 0.50 | ||
Nyssa aquatica | 0.50 | ||
Nyssa sylvatica | 0.50 | ||
Turaka Vepa | Melia azedarach | 0.51 | |
Buxus sempervirens | 0.83 | ||
Turkish Boxwood | Buxus sempervirens | 0.83 | 13 |
Pometia pinnata | 0.60 | ||
Turturan Batu | Koompassia malaccensis | 0.76 | |
Tusam | Pinus merkusii | 0.59 | |
Tut | Morus alba | 0.60 | |
Tutri | Morus alba | 0.60 | |
Tutu | Aningeria altissima | 0.42 | |
Tutu | Aningeria dombeyi | 0.39 | |
Tutu | Aningeria robusta | 0.42 | |
Tutubungan | Heritiera javanica | 0.65 | |
Pometia pinnata | 0.60 | ||
Tuyot | Tetramerista glabra | 0.73 | |
Twenduet | Pygeum africanum | 0.61 | |
Twi | Koordersiodendron pinnatum | 0.71 | |
Tzabitath | Manilkara zapota | 0.71 | |
Tzaput | Manilkara zapota | 0.71 | |
Pometia pinnata | 0.60 | ||
Tzicozapotl | Manilkara zapota | 0.71 | |
Swietenia macrophylla | 0.47 | ||
Swietenia macrophylla | 0.47 | ||
Swietenia macrophylla | 0.47 |
Footnotes:
* Legal disclaimer:
Wagner has compiled species’ average specific gravity (SG) values (wood volume at 12% moisture content (MC) and oven-dry weight) from industry-accepted 3rd-party sources (USDA Forest Products Laboratory as an example) and provides this list for free with no implied warranty. Where an SG value listed in Wagner Meters’ manuals or website has been verified by Wagner, this is indicated as such, and not indicated as verified if a verification process has not been completed by Wagner for that species. Wagner is not responsible for any 3rd-party oversights or errors in their (the 3rd-parties) published SG values.
Where no published average SG value could be found for a species for the wood volume at 12% MC and oven-dry weight basis, Wagner has derived the proper SG value through a robust algorithm (see detailed explanation below under the heading ‘Specific Gravity (SG) Values of Wood and Their Referenced Moisture Content’).
Specific Gravity (SG) Values of Wood and Their Referenced Moisture Content
Wagner Meters’ moisture meters’ species settings are calibrated to wood samples that are at a nominal 12% moisture content (MC). It should also be recognized that the measurement accuracy of non-pin wood moisture meters is almost solely dependent on wood density; that is because wood species that have differing wood density but the same absolute amount of water will have different MC values because the definition of MC is the ratio of water weight to wood weight. Some online and other technical references that cite specific gravity (SG) values for different wood species list the SG when the wood is a different MC other than 12%. For example, some SG values listed are the values when the wood is dried all the way down to where the MC is actually zero. Other listed values are when the wood is “green” at perhaps 80% MC or even higher.
The reason that it matters what the MC was when the SG was determined is that the volume of a wood sample will shrink when it is dried down from high MC values to lower MC values. So as the volume of the wood sample shrinks, the density (SG) of the wood increases because the formula for the wood density is the weight of the wood sample divided by the volume of the wood sample, or more simply the ratio of the weight of the wood to its volume. As the weight stays the same during shrinkage, the volume decreases. Online and other references will not only provide SG values at some specific MC but also their “shrinkage ratio”. The shrinkage ratio is defined to be the percent of the volume of the wood that shrinks per decrease in MC value. For instance, one might see a 2% shrinkage ratio which means that for every 1% drop in MC the wood will shrink by 2% of its volume.
Wagner chose to calibrate its meters at a nominal 12% MC because this is close to where most wood will be in service and will be measured by our meters. Therefore we publish SG values for wood species to be used by our meters that correlate to a 12% MC value. Since online and other references publish SG values at sometimes 0% MC or “green” MC, you will often see different values online than what we publish. We correct these published values by applying correction factors based on MC at referenced SG values and shrinkage ratio published values. It should be noted that a wood sample will not begin shrinking significantly until the MC drops below fiber saturation point, which is generally between 28% and 32%, so we use 30% as the average fiber saturation point.
As an example, let’s say we have a published SG value of 0.50 referenced to 0% MC with a shrinkage ratio of 0.1% of volume per percent MC. We want to convert to an SG value referenced to 12% MC. A sample at 12 % MC will be 1.2% larger in volume (swells 12 * 0.1%). Since 0.50 equals the weight of the sample divided by volume, we now know the volume will actually be 1.2% larger, so the SG should be adjusted by a factor of 1 divided by (1 + 1.2%) or 1 divided by (1.012) = 0.50/1.012 = 0.49). So, in this specific case, the 12 % MC referenced SG value will be slightly less than the published value referenced at 0% MC.