184 DEPARTMENTAL REPORTS. 



mSSOUEI SWAMP FORESTS. 



A report which concludes the stud}' of Missouri swamp forests in 

 progress at the beginning of the fiscal j'ear was completed on June 30, 

 1904. It contains a discussion of the influences which affect the distri- 

 bution and growth of bald cypress, red gum (Liquidambar), and black 

 gum and cotton gum (Nyssa).. The information given will be of value 

 in connection with otlier investigations of these species, and forms a 

 useful contribution to a knowledge of the little known silvical require- 

 ments of these commercially important trees. 



CALIFORNIA BIG TREKS AND BRISTLE-CONE FIR. 



Field studies have been finished and pi-ogress has been made toward 

 the completion of reports on the above <Jalifornia species. 



PACIFIC COAST TANBARK TREES. 



The study of the distribution of Western tanbark* oaks and of 

 other tanbark trees was continued, together with a study of the tan- 

 ning industry depeBdent upon these trees for tanning materials. Par- 

 ticular attention was given to msipping the range of the principal 

 tanbark oak of the coast region apd to the available stand, silvical 

 requirements, and aids to I'eproduction on cut-over areas. Upon this 

 information will be based important recommendations for a sustained 

 yield of a tanning material which is indispensable to the Pacific leather 

 industry. 



Through hearty cooperation of Pacific bark dealers and tanners, a 

 very large number of bark samples was collected for chemical analy- 

 ses, which have been made by the Bureau of Chemistry. The unex- 

 pected discovery of several different types of bark, which yield widely 

 varying quantities of tannin, led to the extension of the study consid- 

 erably beyond the original plan of investigation. This studj' should 

 prove exceptionally profitable in determining the requirements and the 

 special forms of this species which produce the largest percentage of 

 tannin. 



In connection with a studj' of various oak barks much used to adul- 

 terate the standard bark, one or two untried kinds were found which 

 are of genuine value. The possible future use of the abundant alder 

 barks of the coast region has also been under investigation. 



OHIO HARDWOOD FORESTS. 



The study of this subject was terminated during the j'ear. Valuable 

 notes and data resulting from experiments on the water content of 

 green and of air-dried saturated woods were secured. 



TURPENTINE ORCHARDING. 



The work, which the Bureau undertook three years ago, of replac- 

 ing the ruinous " box" system of turpentining by a less injurious but 

 equally productive system has been practically completed. The actual 

 results obtained under the cup and gutter system are far beyond what was 

 anticipated. They consist in a yield of nearly 40 per cent more turpen- 



