History of the heaths
Contrary to popular belief, heathland is not a 'natural' habitat but an ancient 'made' landscape created and maintained by people for over 4,000 years.
The areas that became heathland were once covered in birch, pine, elm, hazel and oak woodland with willow in wetter areas. The pollen records preserved in peat bogs show that woodlands dominated the landscape of Dorset until Bronze Age farmers began to clear the woodland.
2500 - 650 BC from Bronze to Iron Age
Heathland creation was a gradual process which took thousands of years. There were many Bronze Age settlements in Dorset with barrows, burial and cremation chambers which remain on heathland sites today and are protected as Scheduled Ancient Monuments. Trees were cleared to make fields for planting crops; the wood was used for building homes, fences and shelter for livestock, and for fuel. Removing trees and planting crops led to a continuous increase in soil acidity and a reduction in nutrient content; gradually lowering the fertility of the soil making crop production more difficult but improving it for heathland plants. By 1500 BC the forests had largely disappeared and heathlands were established.
650 BC - AD 410 Iron Age to the end of the Roman period
Iron-Age settlements were concentrated along the river valleys and coasts, and the largely unoccupied heaths were used for grazing and fuel. Hill forts were constructed and harbours were established at Poole Harbour and Hengistbury Head. Cereals, fish and salt were traded. Later in this period more settlements grew on the heath. Pottery was made using local clay and fired using gorse and heather. The ashes made good fertiliser.
1200 - 1500 The Middle Ages
In the Middle Ages heaths were used as commons; a name which continues on some sites today. The term "Common Land" means a place where rights of the common may be exercised. Local families were granted these rights: ' rights of common', 'rights of herbage' to graze stock, 'rights of turbary' for gathering peat and turf for fuel, and heather for roofing, fodder and bedding for animals. The people who chose to exercise these rights were known as "Commoners".
1700 - 1930s Changing Times
The heathlands of Dorset spread from the Avon Valley in the east, across Purbeck as far as Dorchester in the west. This continuous block of 50,000 hectares of heathland was fragmented only by the river valleys of the Piddle, Frome and Stour. The heaths were an important part of the rural economy and local communities took a living from them. The Enclosures Act of 1805 determined much of the ownership of the heaths. The first effect of the enclosures were that several of the new private owners planted the heath with pine to 'improve' the area. The population of Bournemouth in 1851 was 695: by 1881 this had increased to 16,000. The heathlands gradually succumbed to the increasing pressures from agriculture, forestry and urbanisation and in 1919 the Forestry Commission were given the task to plant trees wherever they could.
1930s- 1980s Heathland Loss and Deterioration
Traditional uses of the heath declined. The landscape was reduced to about 8,000 hectares and fragmented into over 100 sites. New housing, roads and the need for materials such as gravel, sand and clay for building meant large parts of the heathlands were lost. Electricity, coal and gas was used instead of cutting turf for fuel. Scrub was no longer kept in check by grazing or fuel gathering; birch and pine overtook the open heathland landscape. The ideal habitats for the heathland birds, invertebrates and reptiles were lost in great numbers until only 15% remained in increasingly small fragments. In the 1980s attitudes towards the natural environment began to change. People became more aware of their impact upon the natural world and the Wildlife and Conservation Act in 1981 gave places such as Dorset's heathlands legal protection.
In south east Dorset the underlying geology is Tertiary sands, gravels and clays, ranging from 2 to 65 million years old.
The Tertiary 'Bagshot' and 'Bracklesham Beds' of the Poole basin have created an infertile soil of sands and gravels with clay layers. These nutrient-poor and normally well drained soils favour the development of lowland heaths.