BARK OF OLD OAKS AND OF OTHER SPECIES. 505 



yield being maintaiued, matters will adjust themselves iu a few 

 years' time ; but on the whole, the forest owner will lose, for as 

 long as a purchaser is uncertain of the amount of bark he will 

 obtain, he will generally bid below its proper value. This is, 

 therefore, the most rough and ready of all measurements. 



According to Baur, the average ratio of the bark in cwts. to 

 the peeled wood is as follows : — One stacked cubic meter (35 

 stacked cubic feet) of peeled wood will yield 



Silver-bark O'Ql cwt. 



Seconds 1*69 ,, 



16 years old stem bark 1*45 ,, 



25 years old stem bark 1*95 „ 



Section III. — Utilization of the Bark of Old Oaks and 

 OTHER Trees. 



As the tanner will pay only a very moderate price for the bark 

 from young oak-trees, he cannot easily be induced to utilize the 

 inner bark of old oaks or other trees ; considering that their 

 cortex and bast are generally poorer* in tannin than that of 

 oak coppice-shoots, and that tan prepared from old bark always 

 contains a certain quantity of the worthless external rhitidome, 

 whatever care is taken to exclude it, 



1. Harvesting the Bark of Old Oaks. 



As in the case of poles, so in that of older trees, the bark is 

 peeled in the spring at the opening of the buds, or at Mid- 

 summer, when the second oak-shoots appear. Utilizing the 

 bark of old oak trees, however, involves several causes which 

 are harmful to the forest owner, for felling large oak trees iu 

 the spring impairs the quality of their timber, and many heavy 

 stems would thus fall on ground already stocked with young 

 growth. If, therefore, in order to utilize the bark, the forester 

 neglects the improved quality of his wood obtained by winter 

 felling, he should, at least, exclude areas of young growth, 



* The cortex and bast of oaks, 40—50 years old, according to Wolff, is as 

 licli in tannic acid as that of oak-coppice, provided all corky substance is excluded. 



