64-2 UTILIZATION OF BARK AND ITS CONSTITUENTS. 



bark in spring than in summer, after much of it has passed 

 into the foliage and young twigs of the coppice. Theodore 

 Hartig states that tannic acid is transformed into sugar soon 

 after the foliage has appeared, this begins in the buds and 

 continues with the leaf-development. This fact is evidently in 

 favour of early peeling. 



The state of the weather has considerable influence on the 

 peeling. In damp, calm weather, especially when accompanied 

 by light and warm showers of rain, the bark is peeled most 

 easily early in the morning and late in the afternoon ; this is 

 also the case when the soil is moist, rather than when it is 

 dry : in windy, dry or cold weather and at midday during hot 

 weather, peeling is difficult. The sessile oak is always peeled 

 more easily than the pedunculate oak, but the latter may be 

 peeled about ten days earlier than the former. Larger stems 

 are peeled more easily at the commencement of the season, 

 smaller stems at the middle and end of the season. 



In unfavourable localities, where damage by autumn-frosts 

 is inevitable, the forester is obliged to abandon the whole first 

 year's crop of shoots. Then the injured shoots are either cut- 

 back in the following March, making way for a stronger growth 

 which repays the loss of the first year's wood, or the peeled 

 oak-stems are left standing till the succeeding winter ; then 

 they are felled, and the succeeding crop shoots up early in the 

 spring. This custom is followed in some valleys in the 

 western Schwarzwald. 



[In order to be independent of the natural movement of the 

 sap, H. Maitre, in France, in 1864, adopted with good results 

 a system of peeling oakwood after steaming it, the wood being 

 removed in billets with bark to the factory and there steamed 

 in closed retorts, when bark is easily removed. This system 

 was improved in 1871, by de Normaison, an engineer, who 

 used for the purpose an apparatus weighing only 5 cwt., which 

 supplies a blast of superheated steam. This is used on the 

 felling-area, and by the help of three men and a boy, 15 to 18 

 stacked cubic meters (10 to 12 loads) can be peeled in a day, 

 and yield a ton of bark. A load of wood and 130 gallons of 

 water are used, and the cost is about <2. The advantages of 

 this method are, that the wood may be felled in winter when 



