120 OUR FORESTS AND WOODLANDS 



vary from about two to ten thousand cubic feet 

 (true contents, not reduced by square-of-quarter- 

 girth calculation) per acre, according as the wood 

 may be a thin crop on inferior soil, felled at 

 1 20 years of age, or a full crop on very good 

 soil, harvested at 160 years of age. 



In felling mature oak trees in Britain it is 

 usual to bark them first of all ; and this can 

 only be done during the spring, when the sap 

 is in most active flow. While the price of oak- 

 bark stood high and formerly it commanded a 

 good sale the harvesting of this was an im- 

 portant operation in British woods, and even 

 in the hedgerows where oak grew. This was 

 another very good reason, in addition to 

 the desire for curved timber for shipbuilding, 

 for giving each tree a free space for growth 

 and lateral expansion, as in hedgerows and 

 copsewoods, because the number of branches 

 increased the total quantity of bark, besides 

 making it thick and rich in tanning properties. 

 But the market has now fallen so much that 

 it is often questionable if the advantage obtain- 

 able from the sale of the bark really compensates 

 for obvious drawbacks attendant on the felling 



