>^d 



Commercial Value of Callitris Barks. 



The commercial value of the Callitris barks may be suggested from the 

 following : — The material available is very abundant ; the tannin content is good, 

 often very good, as in C . arenosa and C. calcarata; the colour of the aqueous 

 solutions is not very dark ; the action of the tannin on hide is rapid and complete ; 

 while the soluble non-tannins extracted bv cold water are at a minimum. The 

 amount of resin in the bark is but small, and sparsely distributed, and should 

 hardly cause trouble. 



\\'ith the bark of C . calcarata there seems to be a difference in the deposi- 

 tion of tannin under certain conditions, and the thickest bark investigated, 

 collected at Woodstock, New South Wales, in May, 1907, gave 31-17 per cent. 

 of tannin in the air-dried bark when finally extracted with hot water, and 

 27-8 per cent, when extracted entirel}* with cold water. A somew'hat thick 

 bark of this species, however, collected at \^'ellington. New South Wales, in 

 September, 1903, nearly six 3^ears ago, gave onlv 141 per cent, of tannin, whilst 

 a sf>ecimen from a medium-sized tree, collected at Grenfell, New South Wales, 

 in March, 1909, gave 19 per cent, tannin; one from a small tree collected in June, 

 1909, at Warialda, New South Wales, gave 30^93 per cent, tannin ; and one from 

 a very young tree, collected at Wyalong, New- South \^'ales, July, 1909, gave 

 25-19 per cent, of tannin. 



By referring to the infoimation given under the distribution of the several 

 species, it will be seen how plentiful C. calcarata is, and as its natural habitat is 

 on the hills, which are naturally not so valuable for agriculture as are the plains, 

 it is at once apparent that with a little care and attention, practically a permanent 

 national plantation of enormous dimensions, containing an excellent tan bark, 

 is a\'ailable at once for use, and one that with ordinary precautions can never 

 be exhausted. The young material, too, can also be readily stripped, as the 

 bark peels very easily, so that in the thinning process the material removed could 

 be utilised with advantage. As the greatest amount of tannin occurs in the 

 living portion of the bark, there seems little advantage in allowing it to grow to 

 a large size, and trees 3 or 4 inches in diameter would give probably the best bark 

 for tanning. As the tree grows older the outer cortex thickens, forming deep 

 furrows, and the tannin is not then so good either in qua]it\- or in colour. 



As only one sample of the bark of C . arenosa was procured, comparative 

 results with this species were not obtained. 



All the results were determined on the air-dried barks. 



It is thus possible that the best results would be obtained if the barks were 

 collected at that time of the year when the tannin content is at a maximum. It 



