SOME PHILIPPINE TANBARKS ^ 



By Vicente Q. Gana 



(From the Laboratory of General, Inorganic, and Physical Chemistry, 



Bureau of Science, Manila, P. I.) 



As far as I am aware, mangrove bark, camanchili bark, and 

 alum are the only tanning materials utilized in the Philippine 

 Islands at present. The blending of different barks is not being 

 practiced here, and until more is known of the tanning qualities 

 of the available materials, it will not be possible for the Filipino 

 tanners to produce combination tannages like those used in 

 Europe and in the United States. 



At present the mangrove swamps, which constitute 2 per cent 

 of the public forests of the Philippine Islands, or 207,200 hec- 

 tares,^ are considered the most important source of Philippine 

 tan material, not only on account of the abundance of the man- 

 grove trees, but also because of the fair amount of tannin in 

 the bark. The tannin content and the tanning qualities have 

 been already investigated.' The bark, when used ^ alone, pro- 

 duces a leather which is harsh and dark red in color ; it 

 is almost unsalable. Cox ^ found that the available heating 

 value of the combustible matter [wood — (water + ash) ] in the 

 air-dried bark of six species of mangrove averages 4,625 calories. 

 Although these results were obtained from fresh bark and not 

 from spent tanbark, it is obvious that the waste material should 

 be found useful in steam and power production at the tannery. 



Camanchili (Pithecolobium dulce Bentham) bark comes next 

 in importance and is used to some extent by the majority of 

 Filipino tanners. It»has little coloring matter and produces a 

 dull, light brown leather. Due to the presence of nitrogenous 

 compounds ® an infusion of the bark very soon ferments and 

 develops a disagreeable odor.' In using camanchili bark in a 

 warm climate, antiseptics should be added to the infusion to 

 check excessive fermentation. 



With the object of rendering more materials available to the 



^ Received for publication May, 1916. 



-Bull. P. I. Bur. Forestry (1911), No. 10, 17. 



'Bacon, R. F., and Gana, V. Q., This Journal, Sec. A (1909), 4, 205. 

 Williams, R. R., ibid. (1911), 6, 45. 



'Ibid. (1911), 6, 45. 



' Cox, Alvin J., ibid. (1912), 7, 8. 



'Ibid. (1915), 10, 366. 



' In France a root bark of Quercus coccifera, called "garoville," has the 

 same disadvantage. 



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