Brown forest soils that result from prolonged forestal conditions and which develops under mature deciduous woodland. Brown earths are thought to have covered most of the British Isles and temperate Europe under the great forests which existed during the middle of the present Interglacial. The soil type is penetrated by tree roots and actively worked by earthworms to a considerable depth. The top is well-mixed mineral material and humus. As a result of woodland cover being removed repeatedly, these soils are rare today.