TANNING AIATERIALS 63 



supply of oak bark, hemlock bark and chestnut wood extract. In 1905 

 the average price paid per cord of 2000 lb. for hemlock bark in Penn- 

 sylvania was $7.54 and for oak bark, $8.40. By 1915 the prices became 

 stronger and values from $9.00 to $12.00 per cord were quoted f.o.b. cars 

 at shipping points for hemlock bark and still better prices for oak bark. 



With the growing scarcity of the barks in the East, the Cahfornia tan- 

 bark oak which contains from 10 to 20 per cent or more of tannin was 

 developed. In 1905 over 50,000 cords of an average value of I19.04 

 per cord were produced. In the northwest the western hemlock {Tsuga 

 heteropkylla) began to be developed for its bark. Of the 2200 tons of 

 bark used annually in the tanneries of Oregon and Washington, it is said 

 that two-thirds are of western hemlock. The industry is still in its 

 infancy in the northwest and it is likely that western hemlock will supply 

 a much larger share of the requirements there in the future. It contains 

 from 10 to 12 per cent of tannin. 



The most important development in the tanning industry within 

 recent times in this country came with the discovery of a method to 

 extract the tannin from chestnut wood on a commercial basis. This 

 phase of the industry has developed rapidly within the past twenty years, 

 especially in North Carolina, Virginia and Tennessee, where a plentiful 

 supply of chestnut of suf&cient tannin content is available in the moun- 

 tainous portions of those states. In several of the chestnut extract fac- 

 tories of the South, part of the residue left after the tannin has been 

 removed from the chips is converted into paper. The future of the 

 chestnut extract industry is not altogether. assured, owing to the uncer- 

 ta,inty of the ultimate effect of the blight or bark disease on the chestnut 

 forests of this country. 



• The entrance of foreign tanning materials in competition with those 

 produced in this country has had a profound effect on the industry at 

 large. As the demand for tanning materials increased in this country 

 and the domestic supply became more limited, inaccessible and expensive, 

 it became possible to import exotic tarmins. Quebracho from the 

 Argentine has been imported in steadily increasing amounts since 1900, 

 when the important South American quebracho fields were developed 

 and exported on an extensive scale. The value of quebracho wood and 

 extract imported to this country in 1917 was about $6,575,000. 



Other foreign tanning materials that have entered our market and 

 'have been extensively used within the past two decades are gambler, 

 mangrove bark, myrobalan nuts, sumach and valonia. These and 

 others are described later in this chapter. 



