GEOLOGY AND SOILS OF EPPING FOREST
by R. G. STURDY and R. H. ALLEN
Soil Survey of England and Wales, Writtle Agricultural College, Chelmsford,
Essex, CM1 3RR.
INTRODUCTION
The forest at Epping takes root in some of the most interesting soils and
geological deposits in the county of Essex, and by its very existence is a factor in
the evolution of the soils. Man's influence is present in its management, ad-
mittedly, but by contrast with agricultural land nearby which has been
cultivated, limed, fertilised and drained, the soils of the Forest are little af-
fected, and reflect the other influences of geology, climate, relief and vegetation
acting over thousands rather than hundreds of years.
A hundred years ago the Geological Survey were setting down in map form
the framework for an understanding of the geological history of the Forest, but
much remains to be learnt, particularly about the relationship of the Boulder
Clay to the Pebble Gravel. Current mapping of O.S. 3rd. Edition Sheet 240
(Epping) by the Geological Survey may help to clarify this. As far as soils are
concerned little detailed study or mapping has been done and is greatly to be
encouraged, as therein may lie valuable clues to the recent geological and
vegetational history of the Forest.
Climatically, the Epping Forest district is wetter and slightly cooler than
the rest of Essex, and the following variables, taken from Smith (1976, p. 100)
give some guidance to climatic conditions affecting the Forest's vegetation and
soils. Mean annual rainfall is 665 mm (26.15 in) and the maximum cumulative
potential soil moisture deficit of 150 mm (potential transpiration minus rainfall)
is reached in August. The median date for return to field capacity (zero soil
moisture deficit) is November 25th, excess winter rain is 195mm (7.7 in), and
the mean field capacity period over the winter (roughly the duration of winter
waterlogging of soils) is 135 days (approximately 41/2 months). Annual variation
of these parameters can be quite marked, and standard deviations are large.
An account of the geology and soils from available sources, coupled with
the authors' knowledge of the area is set down below, and is introductory rather
than exhaustive, there not being space to describe in detail all the various
sections and detached parts of the Forest. The place names we have used are
from maps in the Corporation of London's guide to Epping Forest (Qvist,
1971).
Figure 1. Geology of the Epping Forest district; N = Nazeing, E = Epping, BH
= Buckhurst Hill, WF = Wanstead Flats (after Adams, 1974) (opposite).
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