510 bai;k. 



Alps it is preferred to spruce- and l)ircli-l)ark. It is probably 

 uusuitable for tanning sole-leather, but deserves consideration 

 as a substitute ft)r oak-bark iu tanning calf-skin. Owing to the 

 straightness and freedom from branches of the larch, it is more 

 easily barked than oak. It is better to bark it in summer than 

 in spring, as the maximum amount of tannic acid is then 

 attained. 



r,. WlUoic-Barh. 



Willow-bark contains a considerable amount of tannic acid. 

 ]-{esides Sulix caprca and ,S'. alha, the so-called osier-willows are 

 best in this respect. According to data furnished by the Moscow 

 Academy, the quantity of tannic acid in willows varies between 

 8 and 12 '^j^. In Russia, it has for a long time been usual to 

 use willow-bark for tanning, especially in preparing that flexible, 

 water-tight, shining upper leather, for which llussia is so 

 famous. The well-known Danish glove-leather is also tanned 

 with willow-bark. In Germany, little use has hitherto been 

 made of willow-bark, probably on account of the small quantity 

 grown. 



Peelings from osiers are dried in loose heaps and used for 

 tanning, or as litter for cattle. 



Section IV. — Yield in Produce and Revenue of Oak 

 Coppices. 



1. Yield in Produce. 



W oak-coppice is managed for the production of valuable bark, 

 bark must be the principal item in the produce, and the yield iu 

 wood can be considered only as of secondary importance. A 

 sensible management of bark-coppice will, therefore, endeavour 

 to secure all the conditions which have been already stated as 

 essential for the production of a large crop of good bark. 

 Besides the cultural conditions, however, the yield of bark is 

 chiefly influenced by the quality of the locality, and it can be 

 readily understood that owing to the great variability of locality 

 and cultural treatment in the case of bark-coppices, that their 

 yield also varies considerably. As an average yield of the best 



