The type of soil which develops under mature deciduous woodland. Variants of the Brown Forest soil 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 ( see Atlantic). The soil type is characteristically penetrated by tree roots, and actively worked by earthworms to a considerable depth, so that litter from the trees which falls on to the surface is rapidly incorporated into the soil. The top of the profile is marked by a thick, strongly structured and well-mixed horizon of mineral material and humus. Brown Forest soils are fertile and stable, but if the woodland cover is removed repeatedly, or nutrients are removed from the soil by agriculture and animal feeding, they may degrade. In those areas where there is relatively low annual rainfall, a sol lessivé profile may develop. In areas of higher rainfall, or under heath vegetation or coniferous woodland, a podzol may develop. As a result of such changes, true Brown Forest soils are rare today.
The Macmillan dictionary of archaeology, Ruth D. Whitehouse, 1983Copied