Dr A. Pentecost made several trips in 1968-9 but appears to have found no macrolichens other than
Cladonia species. Dr F. Rose visited Wintry Wood in 1970, and made many important finds which
are included with Dr Pentecost's records in Hawksworth et al. (1973). Dr B.J. Coppins visitied Jack's
Hill in September 1972 and recorded 11 species. In addition Dr Rose visited many sites in the Forest
during two visits in 1974, during which 11 species were also recorded on trees.
More recently, in April 1983, Mr J.F. Skinner recorded a variety of species in the Baldwins Hill,
Court Hill, and Little and Great Monk Wood areas. He also named collections from the area made by
Dr K.J. Adams in 1985 and Mr C.W.Plantin 1984. Professor M.R.D. Seaward recorded several species
in the early 1980s in the course of visits to the Epping Forest Conservation Centre (Field Studies
Council Field Centre). Some further records have been made by Mr P.W. James, mainly in the course
of fungus forays in the Forest, but unfortunately these were not made available to us before this
contribution had to be completed.
The Present Survey
Methods
Our 1989-91 survey was conducted with the primary objective of determining to what extent, if
any. the lichen flora on the trees in Epping Forest had changed since the last checklist was published
(Hawksworth et al. 1973). Twenty sites in the Forest were examined, extending from Leyton Flats in
the south to Wintry Wood in the north (Table 1). The sites were selected so as to provide a
representative geographical coverage, and also to encompass parts of the Forest which had been
documented as containing interesting or rare species by previous collectors.
As in the case of our study of lichen recolonization in north-west London (Hawksworth &
McManus, 1989), we recorded the maximum sizes of the largest individuals of each macrolichen
species found in each site in order to provide a guide to approximate minimum dates of establishment.
Less attention was accorded to searching for small individuals of crustose species, and the list
presented here should not therefore be taken as exhaustive.
Previous records included in the Appendix were compiled from exisiting publications and also from
information provided by various colleagues. The time available for this investigation did not, however,
permit us to check the identifications of previous collectors.
Results
The total number of species found on trees and wood in our 1989-91 survey was 41. The richest
site (Wintry Wood; 23 species) was the most northerly examined and the poorest (Leyton Flats; 1
species) was the most southerly (Table 1). No continuous south-north gradient of increasing species
numbers occurred between these two extremes. However, sites south of Woodford Green (and
including the remnants of Walthamstow Forest) were consistently poor with 1-8 species, while the
richest sites were in the main expanse of the Forest between Woodford Green and Epping Town which
had 13-15 species. Further, all the rich sites in the main Forest were in sheltered gullies or hollows,
and often by lakes or rivers (i.e. Baldwins Pond, Bellringers Hollow in Great Monk Wood. Connaught
Water, Dulsmead Hollow, and near the River Ching in Barn Hoppitt). However, in Wintry Wood
lichens occurred on roughly level terrain,
A comparison of the sizes of thalli of Hypogymnia physodes and Parmelia sulcata found in the
Forest with graphs of locally determined growth rates for young thalli of these species (Rose &
Hawksworth, 1981) suggests that most of the former were 7-8 years old, and of the latter 5-6 years
old. The oldest thalli of each of these species found were 9-11 years; these were encountered in the
most sheltered and(or) northerly parts of the Forest (i.e. Baldwin's Pond. Barn Hoppit, Dulsmead
Hollow, and Wintry Wood). To judge from measurements made in a low-rainfall part of Devon (Fisher
& Proctor, 1978) the P. caperata thalli found were unlikely to be more than two years old. and from
observations in Derbyshire (Hawksworth, 1974) those of Usnea subfloridana 3-4 years old. No
published information on the growth rates of Evernia prunastri in the UK appears to be available.
Annual growth increments for several lichens are provided in Paulson (1918). but their provenance
is uncertain and most do not appear to have come from the Forest.
A consistent feature in the survey was that recolomzation by leafy and shrubby lichens was almost
exclusively confined to: (a) trees with nutrient-rich and higher pH bark; and (b) young trees and
branches mainly under 15 cm diam., especially those with rough bark (e.g. Quercus). Large specimens
of Carpinus. Fagus, and Quercus almost invariably lacked young thalli on their trunks and major
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