A heath is a shrubland habitat found mainly on free-draining infertile, acidic soils and is characterised by open, low-growing woody vegetation. Moorland is generally related to high-ground heaths with—especially in Great Britain—a cooler and more damp climate.
Heaths are widespread worldwide, but are fast disappearing and considered a rare habitat in Europe. They form extensive and highly diverse communities across Australia in humid and sub-humid areas where fire regimes with recurring burning are required for the maintenance of the heathlands. Even more diverse though less widespread heath communities occur in Southern Africa. Extensive heath communities can also be found in the California chaparral, New Caledonia, central Chile and along the shores of the Mediterranean Sea. In addition to these extensive heath areas, the vegetation type is also found in scattered locations across all continents, except Antarctica.
Heathland is favoured where climatic conditions are typically hard and dry, particularly in summer, and soils acidic, of low fertility, and often sandy and very free-draining; mires do occur where drainage is poor, but are usually only small in extent. Heaths are dominated by low shrubs, 20 centimetres (7.9 in) to 2 metres (7 feet) tall.
Heath vegetation can be extremely plant-species rich, and heathlands of Australia are home to some 3,700 endemic or typical species in addition to numerous less restricted species. The fynbos heathlands of South Africa are second only to tropical rainforests in plant biodiversity with over 7,000 species. In marked contrast, the tiny pockets of heathland in Europe are extremely depauperate with a flora consisting primarily of heather (Calluna vulgaris), heath (Erica species) and gorse (Ulex species).