126 OUR FORESTS AND WOODLANDS 



timber is in general more likely to be profitable. 

 In oak coppice the crop should be as full as 

 possible, and it should be kept free from admix- 

 ture of other growth, whether hardwoods or soft- 

 woods, except in those places that show themselves 

 unsuitable for the oak. The rotation in which 

 the coppice can be worked, and consequently the 

 number of compartments and the area to be cut 

 over, vary greatly according to the soil, the situa- 

 tion, and the local climate. The best rotation is 

 that which will enable each fall to be made just 

 at the age when the smooth bark, the * pipe-bark * 

 of the oak-stubbs, begins to become rough and 

 fissured, because, after that, it contains less tannin 

 than before. In favourable situations, with good 

 soil and a warm southern exposure, the usual 

 rotation is about fifteen or sixteen years, though 

 varying of course from about twelve to eighteen 

 years according to special circumstances ; but a 

 longer rotation is necessary for less productive 

 soils and a cooler climate. 



For coppice woods the Durmast or sessile oak 

 yields on the whole better returns in bark, and 

 straighter and more vigorous shoots than the 

 English or pedunculate oak. 



