Hockley Woods is described as the largest remaining area of the wild wood, which covered Essex after the Ice Age 10,000 years ago.
The woods are a complex mosaic of different trees, each species growing where conditions are most favourable. Oak and sweet chestnut grow on the higher ground; birch on the most acidic soils; hornbeam on the wet clays; willow, hazel and ash along the streams.
Many of the plants in the wood, such as the wild service tree, wood anemone, wood spurge and cow-wheat will only grow on the undisturbed soils of ancient woods.