II] WOODLAND ASSOCIATIONS 49 



more advantage in colonizing cleared or partially cleared areas 

 than the large and heavy fruits of the oak. In some such places, 

 seedlings of the birch are extremely abundant ; and local plant 

 societies of well-grown birches are common in many of the oak 

 woods. A birch wood at low altitudes in this district usually 

 represents a degenerate oak wood which has been colonized by 

 birches. In ascending the cloughs, many of which are now 

 almost treeless, isolated plants of the common birch are often 

 the last trees which are encountered. Under the peat of the 

 moors, birch remains are locally very abundant. 



The white birch (*Betula alba) is perhaps not indigenous 

 in the hilly woods of the Peak District, as it only seems to 

 occur in the company of such obviously planted trees as the 

 beech, sycamore, peduncled oak, larch and pine. It is never 

 abundant ; and it is absent over extensive tracts and from the 

 more primitive and the more upland woods. 



The alder (Alnus glutinosa) is confined to stream sides 

 and marshy places, where it often forms small societies. It is 

 more abundant in the oak woods than in the ash woods. 



The beech (*Fagus sylvatica), although an almost invariable 

 constituent of the larger woods, has little claim to rank as 

 indigenous. As a rule, evidences of its introduction are easy 

 to trace, either because it occurs in obviously recent plantations 

 or because historical evidence of planting is procurable. 

 Whether indigenous or not, the beech grows well on all the 

 Pennine slopes, both siliceous and calcareous. In favourable 

 seasons, ripe fruits have been observed on trees at an altitude 

 of 1500 feet (457 m.). First-year seedlings are frequently met 

 with in the woods: older seedlings, however, have not been 

 observed; and there is no evidence to show that the beech 

 rejuvenates itself in these hilly woods. Apparently the seed- 

 lings of the beech are all destroyed during their first winter, 

 perhaps because they are unable to endure the alternating cold 

 and mild periods characteristic of the markedly insular climate 

 of the north and west of the British Isles. On the other hand, 

 the rejuvenation of the beech may be observed on sandy and 

 on chalky soils in the south of England, where the tree is 

 indigenous. The analogy of the beech to the pine in the 

 matter of rejuvenation in the north and south of England is 

 remarkable; and it may be that the pine, as well as the 





