Casuarina equisetifolia

Casuarina equisetifolia, the Australian pine tree or whistling pine tree, is a she-oak species of the genus Casuarina. The native range extends throughout Southeast Asia, Northern Australia and the Pacific Islands; including Thailand, Myanmar, Vietnam, Malaysia, Singapore, Brunei, Indonesia, East Timor, and the Philippines (where it is known as agoho pine), east to Papua New Guinea, French Polynesia, New Caledonia, and Vanuatu, and south to Australia (north of Northern Territory, north and east Queensland, and north-eastern New South Wales). Populations are also found in Madagascar, but it is doubtful if this is within the native range of the species. The species has been introduced to the Southern United States and West Africa. It is an invasive species in Florida, South Africa, India and Brazil.

Casuarina equisetifolia was officially described by Linnaeus in 1759 as Casuarina equisefolia. A type was designated by New South Wales botanist Lawrie Johnson in 1989. The specific name equisetifolia is derived from the Latin equisetum, meaning "horse hair" (referring to the resemblance of the drooping branchlets to horse tail). Common names include coast sheoak (coast she oak, coastal she-oak), beach casuarina, beach oak, beach sheoak (beach she-oak), beach pine, whistling tree, horsetail she oak, horsetail beefwood, horsetail tree, Australian pine, ironwood, whistling pine, Filao tree, and agoho.

Casuarina equisetifolia leaf litter suppresses germination of understory plants using a biochemical means or allelopathy. This is one reason it can be such a damaging invasive species in places outside its native range.

Casuarina is an evergreen tree growing to 6-35 m tall.

Casuarina is found from Myanmar and Vietnam throughout Malesia east to French Polynesia, New Caledonia, and Vanuatu, and south into Australia (the northern parts of Northern Territory, north and east Queensland, and northeastern New South Wales, where it extends as far south as Laurieton.