Pear Wood lies to the north of Stanmore Country Park. The post code is
HA7 4LP. It is ancient woodland; there are mentions of the wood dating
back to around 1250. Pear Wood lies on the fast-draining pebble gravel
and claygate beds of the Harrow Weald ridge. Where the ground is open
this gives rise to a heathland vegetation dominated by bracken and
gorse. However, the vast majority of Pear Wood is wooded, the dominant
trees being beech, oak and birch with smaller numbers of sweet
chestnut, hornbeam, crab apple, wild cherry, ash, rowan and Scots pine.
Many plants growing below the trees are characteristic of ancient
woodland, and are therefore not found in the majority of
Harrow’s woods: examples are wood millet, wood poa, creeping
soft-grass, wood and remote sedges, black bryony, hairy wood-rush, tall
brome, wood sage and dog’s mercury.
As the only extensive and relatively undisturbed ancient woodland in
Harrow Pear Wood is managed for nature conservation purposes.
Cutting across Pear Wood is the ancient earthwork of Grim’s
Dyke, which is kept clear of trees to reduce damage to the structure by
tree roots. The origin and purpose of Grim’s Dyke are
unclear: it may date from the Roman occupation or from the 5th or 6th
century; it may be defensive but is more likely to be a boundary
marker. The line of Grim’s Dyke is also clear in Old Redding Nature Reserve to the west, but the connecting section has dissapeared.