SPECIFIC GRAVITY AND WEIGHT OF THE MOST IM- 

 PORTANT AMERICAN WOODS. 



A Sttidy and Compilation. 



By Ali^red GaskilIv. 



The following table is the result of an effort to reduce or har- 

 monize the contradictions that appear in all published figures 

 concerning wood weights. Except for the half dozen species 

 which have been carefully studied by the Forest Service the 

 specific gravities here given have been determined more or less 

 arbitrarily. That is, starting with Sargent's figures, published 

 in Vol. IX Tenth Census, comparisons were made with all other 

 data available. Then specimens of every species were carefully 

 analyzed and compared and densities assigned which recognize 

 the inherent characters of the individual species and eliminate 

 manifest absurdities; such, for instance, as giving to Pinus pon- 

 der osa a density of .47 and to Pinus echinata a density of .61, 

 or making the weights of Quercus alba and Larix occidentalis 

 practically identical. 



It is highly probable that many of these figures will be modi- 

 fied by later studies — entirely possible that one average density 

 will not serve for the wood of a species that grows under widely 

 different conditions. The author will be thankful for any data 

 that will make this table more accurate. 



No claim to original investigation is made further than may be 

 involved in applying somewhat of silviculture and somewhat of 

 common sense to the "as is" determinations from few, or small, 

 or abnormal specimens. 



The figures in all cases are for absolutely dry wood. As any 

 specimen may be ten per cent, heavier, or ten per cent, lighter 

 than the standard without becoming abnormal it is useless to give 

 specific gravities more than two decimal places. For the same 

 reason the cubic foot weights are rounded to even pounds, all 

 being calculated on the basis of a cubic foot of water weighing 

 62.355 pounds at 39 degrees Fahr. 



