QH. II] WOODLAND ASSOCIATIONS 39 



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WOODLAND ASSOCIATIONS OF GREAT BRITAIN 



The various plant associations which are known to occur 

 among British woodlands are summarised below (cf. Moss, 

 Rankin, and Tansley, 1910): 



I. ALDER AND WILLOW ASSOCIATIONS. On very wet soils. 



A. On soils supplied with acidic waters. 



1. Alder and willow thickets of lowland moors. 



B. On soils supplied with basic waters. 



2. Alder and willow thickets of the East Anglian fens. 



C. On fresh soils subject to periodical inundations. 



3. Alder and willow thickets by stream sides. 



II. OAK AND BIRCH ASSOCIATIONS. On non-calcareous soils. 



D. On deep clays. 



4. Oak woods with Quercus Robur ( = Q. pedunculata) dominant. 



Usually coppiced (see Moss, Rankin, and Tansley, 1910 : 

 118). Widespread throughout the lowlands of southern 

 and central England. 



4 b. Oak-hornbeam woods with Q. Robur and Carpinu* Betulus 

 sharing dominance. Rather local in south-eastern England. 

 Frequently coppiced. 



E. On dry sands and gravels. Not uncommon in the south and 



east of England. Locally coppiced. 



5. Oak woods with Quercus Robur or Q. sessiliflora dominant, 



either separately or in combination. 



6. Birch woods with Betula pubescent dominant, or with B. 



pubescens and B. alba (^B. verrucota) in combination. 



7. Pine woods with Pinus sylvestris dominant. 



7 a. Mixed woods of oaks, beeches, birches, and pines. 



8. Beech woods with Fagus sylvatica dominant. Local in the 



south of England. 



F. On the shallow soils of the older siliceous rocks. 



9. Oak woods with Q. sessiliftora dominant. Very common on 



hill slopes in the north and west of Britain at altitudes 

 below 1000 feet (305 m.). Locally coppiced. 



10. Oak-ash woods with Q. sessiliflora and Fraxinu* excelsior 



sharing dominance. Very local. They occur in the Lake 

 District, where the rainfall is very high. 



11. Birch woods with Betula pubescens dominant. Local. They 



occur in the north of England as a zone above the woods 

 of Quercus sessiliflora at altitudes between 1000 feet and 

 1250 feet (381 m.). Much commoner in Scotland. 



12. Birch-ash woods with B. pubescens and Fraxinus excelsior 



sharing dominance. Local. They occur in the Lake 

 District. 



