30 BULLETIN 753, U. S. DEPARTMENT OF AGRICULTURE. 
TABLE 8.—Heat values of cordwood, based on Madison Laboratory weights.—Con. 
Available heat units 
per cord of 90 solid | Percent of short- 
cubic feet (in mil- | ton coal value. 
Species. lions B. t. u.). 
Air-dry. Green. | Air-dry.| Green. 
GCedarineense (Erm dacHrrens).= 2 2 5 gece eh swe ee 14.5 1253 56 | 47 
Orn orord (Clawsoniana oso. 5.0 a o2e 2 A One -eeblese 16.3 15.5 63 60. 
Wiiestenmrech@E pl cata)y is: Joes <n on oe oe Se amber se seme ane 12.1 11.7 47 45 
Wihtte CEvoccidentilis).s245. 2 noe es aS ies 10.7 43 4) 
Cupressshale CR distiehuim) 1.2022 Sole ee ee 16.4 14.5 | 63 56 
Mellows (G- nootkatenSis)-2 24-2292 eee eee ee 15.8 1a! 61 58 
Douglasfir: Pacific coast (P: taxifolia):. 9! 2220 £77 17.3 68 67 
Gc yiMoOun tainSis s/s Joo se Roe, ae eae VE ES 15.6 1G! 60 58 
ESL pes: IASIOCAEPA)- 22. cos ee ose eases ac ene eae ees 12.0 11.5 46 44 
ATMA DINS CACaMIADRHS Oc cce sou te We oes MDs Soe ae 15.1 12.9 58 50 
balsam Gre Dalsamen) =. 282 keg So Nas eo eo 125 he 52 46 
Bowman white GA erandis) 0. 2a ae 2 Se ess Se 15.1 13.3 58 51 
Noha GAs MODIS yai5 2% — oe aL eS See ee ene ones 14.3 165-7) 55 53 
Silver, White CA 7concolor) 2.02.2. 290. 0. So) 2s 2 14.3 11.1 55 43 
iEramlgek plack-(‘Ts. mertensiana)s.— 2. 20-5 sac ede eee ee oe 7.2 15.7 66 60 
I2StGrRy (CE CAMAGECHSIS)! Uo jaceus. fener Sows aes See 15.0 12.8 53. 49 
WhKeSLcEn CE, heterophylla). 25a 2 oe oc ee ee 15.0 13.5 58 52 
arch awestern Gis occidentalis). 2oo- 6 0k Soares ee. ea 19.3 17.9 74 69 
aStermn Ch omericanay: ste ci. Se eat eS Se ee 19.1 18.1 73 70 
Pine, Cuban, slash (P’. heterophylla). <...= 2-22. 22-.2.2222222<- 22.4 21.6 86 83 
neha @laOhyariCatc)- 2.320 S202 20 eee ee cee es oe ene oe 15.7 13.4 60 52 
AKGSEF OE TOLFEO YD) y- sc ee gue eae ee Ae aw. al hee oe We 15.0 12.9 58 50 
Paplatiy (Pe taeda) os. 2.2 Se ee Sn ee ee aoe : 19.9 18.1 77 70 
madconole GEM Contored hs os ae na cee es ae os ee 15.0 13.8 58 53 
Wonclerh (Ps paluSpris). 58. 2 ieee see eee ee a a et ee 22-0 Sade eer 85 81 
INGEWaly CE FOSIROnD 2) got OTe. 2 SP OR Set eee 17.8 16.8 68 65 
TATA Xalo! (Ges F7G 0) Re ae Be Ti Salk coh eee Be gy cried eh ln 18.5 16.4 71 63 
IR OnE Senatina pices 5 oer e ey Fel hie 2 Se eee RS 20.0 18. 7 77 72 
SHorbealGe echmatay. 25) 2 00s eee er. ey tae ee ae 19.9 18.5 77 fal 
Saebercats (Es PS IIGHEP AR) oo soe che tea eck Se ee eR ee Be 14.3 3 By; “55 45 
habla Mountain CE punrensy.2 ee eee ee Ae een 19.3 7.2 74 66 
Western white (P. monticola).............-. A SE Sireu sas ste 2 15.7 14.6 60 56 
Westerm yellow (Ps ponderosa):. 2. 28. oo. 2 Shs eee 15.0 took 58 50 
WER Ee: CES SUEO RIS) soe eg IN FE ae 14.2 12.9 55 50 
Spruce, Engelmann (P.engelmanni) ..................--.------- 11.9 10.5 46 40 
(Red CR EG DEa hee tte She Ye ee Saker 15.0 14.2 58 55 
Skt oR Gly StL CMOHSES oe ciae cece nar aha ee Pec er 13.5 1 bay 52 49 
INEnie CE A eangdensis hs 3 gsc et Joe ae eR ee Ga eee 14.1 13.5 54 52 
MWe aiWweSteri (l= DEGUEOIA = sue sa. ween a nn ka ae Sea 24.4 730 94 89 
Frech wood (cs SOMPCEWITGNS) solo" Se Sn i 14.3 12.9 55 50 
Weal tong tor, (2-240 ponds). 804 oe eee ee) a 29-4 ee ee re ee 
SHEEGCON (2.00e Pats) 626. 2S Tei ee a se ae | 96: Otis 2 ee | eet het ae 
Norte.—Valuses given for resinous woods are low, since resin adds to heating value; for instance, dry 
longleaf pine with 20 per cent resin has a value ofapproximately 26,400,000 B. t. u., imstead of the 22,000,000 
given in thetable. The amount of bark in a cord of wood also affects the heating value; forinstance, bark 
of birch, Douglas fir, western yellow pine, and others has a higher value than the wood. Much of the 
theoretical value of both wood and coalislostin use. Whileanthracite and soft coal have about the same 
theoretical value, only from 70 to 75 per cent of this value is realized with anthracite and from 60 to 65 per 
cent with bituminous coal. Values decrease as temperature of fluegasesincreases. To get values for wood 
only partly seasoned it may be assumed that in most casesit will be about half seasoned in three months, 
two-thirds seasoned in six months, and entirely air-dry in about a year. 
It may be. seen from this table that the heating power of a given 
quantity of green wood is not so very much below that of the same 
wood after it has been dried. The choice of wood for fuel does not, 
however, depend entirely upon its calorific power; other factors, such 
as freedom from smoke, completeness of combustion, and rapidity of 
burning. play a very important part. Green wood is not only much 
heavier to handle but it is also harder to ignite and to keep burning, 
unless mixed with dry wood or with coal,and makes more smoke. For 
a slow fire green wood or a mixture of green and dry wood is 
often more satisfactory than dry wood alone, since the latter burns 
up rapidly and much of its heat escapes up the pipe. 
