188 BATIK. 



(c) System of Management. — All oak-bark woods are managed 

 as coppice, because the quickest growth in youth is attained by 

 coppice-shoots, rather than by seedlings. Besides pure coppice, a 

 mixed system of field-crops and coppice (Ger. Ilackinihl) is also 

 employed. Although much benefit to the production of bark has 

 been ascribed to the cultivation and burning of the soil which 

 accompanies this system, it cannot be admitted that cereal crops 

 are compatible with a rational method of bark production. 



Without considering the impoverishment of the soil which 

 must result at each cereal harvest, the disadvantage of the 

 method consists chiefly in the fact that the coppice is in this 

 case kept much more open than is consistent with a large pro- 

 duction of bark, that the earth at each felling is witlidrawn 

 from the stools in order to supply loose soil for the cereal crop, 

 and that it is washed-down from slopes. Even from financial 

 and national-economic points of view, this mixed system is 

 inferior to simple oak-coppice. 



(d) Rotation. — The bark should be peeled when the bast is 

 thickest, and before the cortex cracks owing to the formation 

 of rhitidome ; from this period the bast, which contains twice 

 as much tannic acid as the rhitidome, will thicken no longer. 

 Such bark in Germany is termed Spicf/cl-rinde, silver-bark, and 

 is most highly esteemed by tanners. Soon afterwards rhitidome 

 is formed, and this inferior bark is termed Rauh-rindr, or 

 coarse bark. In the best districts for oak-bark, where its pro- 

 duction is properly regulated, the coppice is felled when from 14 

 to 20 years old, as then the best bark is obtained. Wherever 

 there is a wish to obtain fairly utilizuble wood as well as bark, 

 as for instance, in many municipal and private woods in Fran- 

 conia, Wiirttemberg, itc, the rotation is fixed at 25, or even 30 

 years. 



The tanner estimates the value of bark by the appearance of 

 a transverse section. If a transverse section of a piece of 

 young bark is inspected, two layers are noticeable, a reddish 

 brown outer layer, the true bark or rhitidome, and a light 

 coloured layer, the cortex with the bast. The thicker the inner 

 whitish or pink young cortex and bast, and the thinner the 

 rhitidome, the more tannic acid a bark contains. That period 

 of its life in which oak-coppice is growing most vigorously, in 



