The Woodlands of England. j 25 
Within the series we may distinguish (A) Oakwood Associa¬ 
tions, (B) an Oak = birch = heath association, and (C) a Birch- 
wood association. 
(A). Oakwood associations. These are by far the most 
widely distributed of British woodland types, occurring as they do 
on the stiffest clays, on all the loams and fine-grained sandstones 
(whose soils when wet “ puddle ” like clays), and also on the 
coarser sands and gravels, provided they are sufficiently moist. 
Quercus Robur ( =Q. pedunculata) is the dominant tree on these soils, 
but 0 . sessilifiora may also be found on the more coarsely grained 
soils alternately dominant or sharing dominance with 0. Robur. 
On the siliceous shallow-soiled (dysgeogenous) palaeozoic and igneous 
rocks of the west and north, Q. sessilifiora is the dominant species, 
to the exclusion, for the most part at least, of Q. Robur , except 
where the latter species has been planted. Q. sessilifiora may also 
be dominant on the geologically more recent sandy rocks of the 
south of England, especially where the soil is rendered shallow by 
the occurrence of a hard layer a few feet below the surface, e.g., 
over the chert of the Hythe beds of west Kent, and over the locally 
massive sandstones of the Tunbridge Wells beds. 
Owing to the great variety of the soils on which the oak is 
dominant, the associated trees, and especially the ground vegetation, 
of the oakwoods show a wide range. The following associations 
(or perhaps groups of associations) may be conveniently distin¬ 
guished, their characteristic ground vegetation being related to the 
soils on which they occur. 
(a) Damp Oakivoods. These occur on clays and on most of 
the loams (except where the soil is permanently very wet), e.g., on 
the London Clay, the Gault, the Weald Clay, and much of the “ clay 
with flints ” covering the chalk plateaux in the south of England. 
Quercus Robur, the pedunculate oak, is always the dominant tree. 
Locally, as on the London Clay north of London, and on the clay in 
parts of the Weald of Sussex, the oak is accompanied by hornbeam 
(Carpinus Betulus) which is often abundant, and usually, but not 
invariably, coppiced or pollarded. In these districts, hornbeam 
coppice is often mixed with, and sometimes replaces, hazel coppice. 
The ash ( Fraxinus excelsior) is a common and sometimes an 
abundant constituent of the damp oakwood, especially on deep 
moist soils. Along stream sides it is frequently locally dominant, 
and here, with its associated ground vegetation, it may be regarded 
as the “ tailing off ” of the Alder-Willow-type of vegetation previously 
described. In the copsewoods of the south of England, ash is 
