30 BULLETIN 153, 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. 
Cedar, incense (L. dacurrens).............----2---0--e eee eee eens 14.5 12.3 56 47 
Port orford (C. lawsoniana)...............---- egis 16.3 15.5 63 60 
Western red (T. plicata)................---- i 12.1 11.7 47 45 
White (T. occidentilis)..................---- i 11.3 10.7 43 41 
Cypress, bald (T. distichum)-............ Sas - 16.4 14.5 63 56 
Yellow (C. nootkatensis)............ 15.8 15.1 61 58 
Douglas fir, Pacific coast (P. taxifolia)..- Wee 0 17.3 68 67 
Rocky Mountains.......... wee cbse 15.6 15.1 60 58 
Fir, alpine (A. lasiocarpa).......-.------ 12.0 11.5 46 44 
Amabilis (A. amabilis). - z 15.1 12.9 58 50 
Balsamy (Av balsamea) eases eseeaee es saeeace = 13.5 11.5 52 46 
Howlandiwihite\ CAs erancis) sso. eee ee cese saan a eee eee 15.1 13.3 58 51 
INO DEEN nobilis) eee ee i eos Me Ss eae 14.3 13.7 55 53 
SilivenswhitelGAsiconcolon) psec seeeeeeces eee e sea e ae eeee eee 14.3 11.1 55 43 
EHemlock,blacki(RSmertensiana) psec -ee ce eee ee eee 17.2 «1527 66 60 
Hasterm (Lcanadensis) stecacscesece ae sees eee eee eee 15.0 12.8 58 49 
Western Ciheterophylla) Pasecseasee eee cee eeee eee ee eters 15.0 13.5 58 52 
Larch, western (L. occidentalis)...........---------------------- 19.3 2 Ue) 74 69 
Eastern\ (us americana) see acess nee eee meester eee cree eee 19.1 18.1 73 70 
Pine, Cuban, slash (P. heterophylla). .......-..-.---------.------ 22.4 21.6 86 83 
eck CEs Gly al Caytien)) es RS ey a Le eC ot er a 15.7 13.4 60 52 
» deity CPi einng)) cocost oosbossuesascoosnoascssoousssoness 15.0 12.9 58 50 
Moblolivg(batacda)isn och acons coc casinos beeen eee 19.9 18.1 77 70 
Modrepolel(Bacontonta)seseeeeee cee eee eee eee eee 15.0 13.8 58 53 
mongleaf((Pepalustris) gee eae Sone ee eco eee ene 22.0 21.1 85 81 
INOTWw aya (PE TeSIMOBa) See: lan eas cee scene te tee ee eee eteee 17.8 16.8 68 65 
Pit Chi GR Teta ay) ee a a ee Te Nelle ee OT al gh tes sea 18.5 16.4 7 63 
PONG CRASOLOEIIA) Soe sete es Sac Aes eee ee eee eee , 20.0 18.7 77 72 
Shortleat(@P: echinata) 22ers ee as ee ey 19.9 18.5 77 71 
Sugar Ge slambertiana) pene oee soe cece eee eee eee eee eee eee 14.3 11.7 55 45 
Ubi) o} ks) I oybuat isin (BQ jowbakeAs) noe bohS soobonoboosoeosmoSocoode 19.3 17.2 74 66 
WiestermiwhiteGbsamonticola)s een ceee seen eeeeeeeeee ence 15.7 14.6 60 56 
Western yellow (P. ponderosa)..............-...-..-- eae 15.0 13.1 58 50 
WUT Ot CE ASELG IOUS) ess ce ote tees cas ocelot atsroele arate et ete oe 14.2 12.9 55 50 
Spruce, Engelmann (P.engelmanni)...............-....-......- 11.9 10.5 46 40 
Red(GLerubra) eee Soe eee cect ee eS eee 15.0 14.2 58 55 
Sitka(heSitChensis) sess wesc ciate cette cs Cae ee eee nee 13.5 12.7 52 49 
Wihiter@P..|canadensis) is eae oe ee rc ratte estetehetoe 14.1 13.5 54 52 
Wow, western (Tibrevitolia)\ pe. ss. ss ac cenee eee eee cee eer 24.4 23.2 94 89 
Redwood (Sasempernvirens)/ssescsecnecee seer econ ee eeee eee 14.3 12.9 55 50 
Coalfloneitonl(2)240pounds) seats = = pee e eee eee eee eee eee 74S el aa eae [Saat ne yeah A eyes Se 
Short ton C2'000spounds) eee se et ck be ccm cereietceieee cee HY aoobaccoacallbaed BSH acuerdo 
Note.—Values 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., instead of the 22,000,000 
givenin thetable. The amount of bark in a cord of wood also affects the heating value; for instance, 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. While anthracite and soft coal have about the same 
theoretical value, only from 70 to 75 per cent ofthis value is realized with anthracite and from 60 to 65 per 
cent with bituminous coal. Values decrease as temperature of flue gasesincreases. To get values for wood 
only partly seasoned it may be assumed that in most cases it 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. 
