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THE ESSEX NATURALIST
"town" is 1° or 2° warmer than the "country" in winter, and this is con-
firmed from the January minima of Tottenham, Enfield and Chelmsford
(37.3°, 34.3°, 33.8°F.). As Pig. 2 shows, Walthamstow, though low lying
and naturally a collecting place for frost draining off the ridge behind it,
lasts as an island of warmth far into winter nights.
As far as they can be detected, the microclimates of Epping Forest show
some interesting variations, partly due to its position on a narrow ridge
generally bounded by the 250' contour, and partly due to the varying density
and composition of the forest. Apart from beech and birch on the sandy
ridge cappings, the forest is characterised by pollarded oak and hornbeam.