68 VEGETATION OF THE PEAK DISTRICT [CH. 



The ash woods on the limestone slopes have the same 

 altitudinal range as the oak {Quercus sessiliflora) woods on the 

 slopes of the sandstones and shales ; that is, they range from 

 the valley bottoms up to about 1000 feet (305 m.). 



Semi-natural Woods and Plantations 

 on the Limestone Slopes 



Some of the slopes of the limestone hills with a deeper and 

 a damper soil are utilized by the foresters for the growth of 

 marketable timber; and the beech {*Fagus sylvatica), the 

 sycamore (*Acer Fseudoplatanus), the larch (*Larix decidua), 

 and other trees are planted. Owing to the dip of the rock-strata, 

 one side of narrow valleys is usually damper than the other; 

 and hence it is unusual to find that the opposite sides of the 

 dales have quite similar vegetation. One may find, for example, 

 that the damper slope is planted up with beeches, sycamores, 

 larches, and other introduced trees, and that the opposite side 

 is characterized by a perfectly spontaneous ash wood ; and thus 

 it is in parts of Lathkilldale. In some cases, where alien trees 

 have been planted on the site of a previous ash wood, the 

 primitive flora lingers on for some time. For example, the 

 lily-of-the- valley {Convallaria majalis) and the broad-leaved 

 helleborine {Helleborine latifolia) still linger on, but do not 

 flower freely, under introduced beeches in Lathkilldale. In 

 other cases, the alien trees have been planted on calcareous 

 grassland. In such plantations, one does not find the rarer 

 and more characteristic plants of the ash woods ; but some 

 of the more general and ubiquitous woodland species, such 

 as Geuni urhanum and Lychnis dioica, sooner or later invade 

 them. On the accompanying vegetation maps, the great 

 abundance of introduced trees is, where possible, indicated by 

 the initial letter of the alien tree being planted over the wood- 

 land colour; and thus it is often possible to infer from the maps 

 whether alien trees have been planted in a wood or not. The 

 maps, therefore, have a far greater value to foresters than any 

 previously constructed maps, such as the Ordnance maps or 

 the small scale maps issued by various publishers, as even the 

 best of these maps do not attempt to distinguish more than 

 deciduous woods and coniferous woods ; and even this simple 



