BOTANICAL ASPECTS OF PAPER-PULP AND TANNING INDUSTRIES 529 



WATTLE BARK. 30 to 40 per cent tannin. Second most important material 

 now imported. From several species of Australian acacia, but almost entirely 

 from black wattle (Acacia mollissima = A. decurrens var. mollis), now ex- 

 tensively cultivated in South Africa, especially Natal. Other Australian species 

 contributing to the cultivated African supply are green wattle (^4. decurrens) , 

 silver or blue wattle {A. dcalbata = A. decurrens var. dealbata), and golden 

 wattle (A. pycnantha). 



Consumption and uses. In 1950, the latest year for which complete figures 

 have been assembled, the consumption of all categories of vegetable tanning 

 materials in the United States was as indicated by the data in table 1. This 

 consumption took care of only 30 to 35 per cent of all leather, on an area 

 basis, produced that year; the remaining 65 to 70 per cent was processed by 

 non-vegetable agents, principally chromium salts. 



While 95 per cent of all industrial tannin is utilized in leather processing, 

 the remaining 5 per cent is important to certain other industries. Principal 

 among them is that of petroleum, where up to 40,000 tons of quebracho and 

 other extracts, along with pecan shells, has been used in one year to reduce 

 the viscosity of oil-well drilling muds. Lesser amounts go into preservative 

 treatment of lishing nets, ink manufacture, boiler-water treatment, plastics, 

 and medicinal preparations for treating burns. 



An economic problem and possible botanical solutions. In 1956 the Ameri- 

 can tanning industry consumed about 120,000 tons of 100 per cent tannin 

 extract. Not more than 40 per cent of this was furnished by domestic 

 sources. The most important of these, namely, reserve supplies of chestnut 

 wood extract — providing only about 10 per cent of the over-all needs — was 

 rapidly nearing exhaustion and would not be replenished, according to present 

 indications, for future demands. Chestnut oak and eastern hemlock barks, 

 the second and third most important domestic sources, are not economically 

 available in sufficiently large quantities to be significant. The most important 

 of the foreign sources, quebracho wood in Argentina and Paraguay — supply- 

 ing 40 per cent of our needs — is becoming progressively more inaccessible in 

 the South American jungle, is controlled by a cartel, and is always subject 

 to export embargo because of an expanding South American tanning industry. 

 And the second most important foreign source, wattle bark — furnishing 25 

 per cent of our needs — is largely shunted into Commonwealth tanneries be- 

 cause of Empire preferences. In brief, of the three principal sources of 

 vegetable tanning, furnishing 75 per cent of our needs, one is approaching 

 extinction and the other two can be discontinued at any time by war or 

 embargo or rendered prohibitively costly by economic factors or political 

 machinations. 



The American tanning and other tannin-utiUzing industries are thus seri- 

 ously threatened by a shortage in their principal raw material. This shortage 

 can be alleviated in three ways: 



