260 OUR FORESTS AND WOODLANDS 



retained in the woods so long as actuarial cal- 

 culations (for which the rate of growth shown 

 by the trees themselves and the local market 

 prices afford the only practical data) show that 

 the woods are still in full vigour, and that the 

 increment being annually made (judged by its 

 equivalent under the monetary standard) is not 

 already beginning to diminish. 



Experience shows that in highwoods the 

 longer periods of rotation prove advantageous 

 on the better classes of land, while in copse 

 and in coppices the shortest periods are only 

 permissible on good soils and favourable situa- 

 tions. That is to say, on the better classes of 

 woodland soil highwoods can be profitably grown 

 with a longer rotation than on poor land ; while 

 in copse and coppice the fall can be repeated all 

 the more frequently the better the quality of the 

 land, because there is not the same danger of 

 deterioration by frequent exposure. 



Unfortunately, no average data on any large 

 scale are as yet available from British woods 

 to prove these facts, though they are matters 

 of common experience in practice. In default 

 of such statistical tables for Britain, it may 



