REPORT ON THE LICHENS OF EPPING FOREST. 137
Forest have probably suffered a check, from which, owing to
the systematic felling practised of recent years by the Conser-
vators, and the greater amount of light, moisture, and air con-
sequently obtained, they are now recovering. Previously to the
passing of the Epping Forest Act, the pollarded trees were
"lopped and topped" at regular intervals of time. This allowed
of abundant light and rain reaching their trunks, and even of
permitting the growth of heather between the most thickly-set
trees. With the abolition of the lopping rights, however, long
poles grew upwards from the pollarded crowns and formed a
shade-canopy. This speedily killed off the heather and other
undergrowth, and must incidentally have destroyed the lichens
which flourished, no doubt, among the heather as well as on the
tree trunks themselves.
The periodic thinnings now carried on by the Conservators
are already having their good effect, and the hornbeam pollards,
even in the densely-grown Loughton Manor, yield a fair crop of
species of the genera Opegrapha, Pertusaria, and Lecanora, though
frequently in an imperfectly-developed condition as regards
spores. We cannot but think that the recent determination of
the Conservators to thin out the trees "by areas," opening up
treeless glades of an acre or so in extent, rather than felling an
individual tree here and another there, will have further
beneficial results as regards the lichen flora of the woodlands.
As to the third cause of diminution—the increase and exten-
sion of villages in the neighbourhood—this has had very little
effect upon that part of the Forest best suited for the growth of
lichens, viz. :—Great Monk Wood, as a centre, with a radius
extending northward to Copped Hall Lodge, Ambresbury Banks,
and "Genesis Slade," and southward to Loughton Camp,
"Kate's Cellar," and High Beach.
Localities, such as Hoe Street, Wood Street, and Chapel
End, in Walthamstow, Hale End and Lea Bridge Road,
included by Crombie, have ceased long ago to produce any
species of lichen, except one or two that flourish in urban
areas. Human habitations have increased around Chingford
station, and by the "Woodman" on the Bury Path; but Hawk
Wood and Bury Wood were not previously localities very
favourable for lichen growth, so that little has been lost in those
parts. Owing to the direction of the prevalent winds, we are