PERIODICAI, LITERATURE 809 



cubic feet, but is not recomended for extracting stumps. It fells 120 

 year old Scotch pine at the rate of 350 cubic feet of timber and 1.5 to 

 3 cords of stump wood per hour, but is not satisfactory for felling 

 hardwoods. It is of no interest in regions where logging is easy and 

 not expensive, but can be used to advantage for removing logs in moun- 

 tainous country without good roads or in other regions difficult of 

 access or where team transportation is very costly. Its usefulness in 

 felling coniferous trees is limited to cases where it is desired to extract 

 the stumps, as is usually the case, and then only when the labor of 

 woodcutters is particularly expensive. S. T. D. 



Huffel, G. Etnploi de tracteurs a chenilles dans les exploitations forestieres. 

 Rev. Eaux et Forets, 59 :40-42, 1921. 



This article gives a good general description of 

 Chestnut Wood the production and use of the tannin of chestnut 

 Tannin wood. Of special interest to the forester are the 



statements in regard to the effect of age of the 

 tree and locality on the tannic content. It is stated that trees about 15 

 years old and six inches in diameter show a tannic content of approxi- 

 mately 7.83 per cent, whereas trees 90 years old and 30 inches in diam- 

 eter show a tannin content of approximately 9.72 per cent. The tannin 

 content of the wood in the southern part of the belt is approximately 

 10 to 11 per cent, whereas wood grown in the north or even in the 

 higher altitudes shows approximately 7 to 8 per cent tannin. 



L. F. H. 



Chestnut Wood Tannin. Robert W. Griffith, Journal of American Leather 

 Chemists' Ass'n., June, 1921. 



Production of tannin from oak wood began 

 Oak Wood and about 1883 in Slavonia and Croatia, developed 

 Oak Wood Extract later in France and North America, and during 

 for Tanning the war was tried in Germany. Results of 

 analyses are given, which show that the tannin 

 content increases with age of the tree, and is greatest in the lowest part 

 of the bole. Sapwood contains very little tannin, while the greatest 

 amount is in the outer layers of heartwood. Young trees (under 20 

 years) contain too little tannin to be worked profitably. Tannin con- 

 tent of at least 5 per cent (air-dry weight, moisture content about 14.5 

 per cent) is necessary for profitable operation, but the amount present 



