36 • DEPARTMENTAL REPOETS. 



hemlock, tamarack, and Norway pine furnished helpful information 

 on the amount and influence of water absorbed by different woods, 

 and establish that wood does not begin to shrink until its moisture 

 content is reduced below the saturation point. The per cent of 

 moisture which suffices to saturate the cell walls of wood varies 

 between 20 and 30. 



The studies now being carried on include tests of the strength of 

 several species of wood when subjected to reversal of stress, the 

 results of which are expected to throw light upon the question of 

 fatigue in telephone and telegraph poles; investigation of the effect 

 of various drying and treating processes upon the strength of wood, 

 including treatments in which superheated stfeam is used, and dry- 

 air treatments in which high temperatures and air at high pressures 

 are used; studies of various other problems connected 'with the 

 moisture content of wood ; tests of small specimens of wood under 

 dead loads, from which it is hoped to derive factors enabling the 

 engineer to apply results obtained from tests under gradual loading 

 to the design of structures Subjected to dead loads; further tests of 

 California eucalypts, including some important new species ; and 

 work on the shrinkage factors of Douglas fir, western hemlock, and 

 several other western woods. The testing of western hemlock is still 

 in progress, and tests are being continued to determine the strength 

 of timber obtained from the National Forests. 



STATISTICS. 



During the early part of the fiscal year the compilation of the 

 statistics of forest products collected during the preceding year was 

 completed and published. On January 1, 1907, the collection of 

 these annual statistics of forest products was transferred to the 

 Bureau of the Census, under a cooperative plan which greatly 

 increased the efficiency of the work. In 1906 reports were received 

 from leas than 12,000 lumber manufacturers; in 1907 from more 

 than 21,000 manufacturers, with corresponding increases in other 

 lines. The information concerning the annual drain upon the for- 

 ests of the United States is now far more complete than ever before. 

 The National Lumber Manufacturers' Association continued its coop- 

 eration in the statistical work, and has taken an active part in 

 collecting the data. Preliminary circulars showing the total produc- 

 tion of lumber, lath, and shingles, the consumption of tanbark, cross- 

 ties, pulpwood, telegraph and telephone poles, and the wood used 

 in the manufacture of tight and slack cooperage stock, veneerj and 

 for distillation during 1906 were recently issued. The final reports 

 are being prepared. 



SPECIAL STUDIES. 



A special study of dead and mature timber on the National Forests 

 involved field investigations in the Battlement Mesa, Beaver, Gun- 

 nison, Holy Cross, Jemez, Medicine Bow, Montezuma, Pecos River, 

 Pikes Peak, White River, and Uinta Forests. 



A statistical study of the uses of wood was made by securing 

 reports from the leading manufacturing concerns on the amount and 

 kinds of wood used by them for various purposes. Current quota- 

 tions of the market prices by grades of all the commercial kinds of 



