The Woodlands of England. 143 
The ground vegetation of the ash-birch woods is of the same 
type as that of the ashwoods, though less luxuriant; and this again 
is doubtless owing to the more severe climatic conditions. 
Thus, this association shows some relationship with the upper 
hill woods of the oak and birch series, in fact a convergence with 
the birchwood associations of that series, namely those woods 
representing the extreme conditions of altitude on siliceous soils; 
just as, at the other end of the scale there is a relationship between 
the oakwoods of the non-calcareous clays and the ash-oakwoods of 
the calcareous marls. 
(C). Beechwood Association. 
Beechwoods are the characteristic woodland type of the chalk 
escarpments and valley sides of south-eastern England, i.e., where- 
ever the chalk forms the actual subsoil. In these situations they 
are found fringing the Weald on the north, west and south, i.e., 
through Kent, Surrey, Hampshire and Sussex. They are, however, 
absent from the extreme eastern end of the North Downs west of 
Dover to about Wye, and also from the eastern end of the South 
Downs, westward from Beachy Head, a tract of country singularly 
bare of trees. From Lewes westwards to Steyning a few scattered 
remains of beechwood occur here and there on the escarpment. 
Beyond Steyning they increase considerably, while in the neighbour¬ 
hood of Arundel and westwards to the Hampshire border are some 
of the finest beech woods in England. 
On the Chalk-outcrop, which runs in a generally north-east 
and south-west direction through the greater part of England, 
the finest development of beechwoods is on the Chiltern Hills of 
south Buckinghamshire and east Oxfordshire, and on the chalk 
slopes on either side of the Thames valley. From this centre, they 
thin out pretty rapidly both to the north-east and to the south-west, 
so that in Cambridgeshire and Wiltshire respectively, they are 
represented only by scattered patches, many of which are clearly 
plantations on grass or arable land with none of the characteristic 
plants of the beech association. 
The fine beechwoods of the Cotswolds are apparently a 
westward extension of the Thames valley area. 
Of the causes of this circumscription of natural or semi-natural 
beechwood, we know very little. It seems likely that beech is 
speaking geologically, a comparatively recent migrant into this 
country from the Continent. Such a view is supported by its 
