The Casuarina is a tall evergreen tree that can grow up to 35m tall. Although it resembles a pine tree or conifer in appearance, it is actually an angiosperm (flowering plant) and not related to the non-flowering pine family at all. The crown is distinctly conical in young trees, but becomes more irregular with maturity. It has a delicate, wispy appearance. The trunk of the tree is straight and branching only begins from 10m above the ground. They may occasionally have buttress roots.
The leaves of the Casuarina are tiny and pointed scales arranged in whorls of 6 to 10 at the joints of twigs. The delicate needle-like twigs are greenish. Photosynthesis takes place in the twigs instead of the tiny leaves.
The monoecious flowers are tiny and wind pollinated. The tiny male flowers appear on short spikes while female flowers appear as pink fluffy bits on a short stalk. These will turn into green cones. Upon ripening, the cones will turn brown and the bracts on the cone will open up to release small winged nuts. The cones are dispersed by wind.
The bark has medicinal value and is used to treat dysentery and diarrhoea. The twigs are used for swelling and as a wash for beri beri.
The wood of this tree is extremely hard and dense, and has been used for construction of stilts, poles and fences in coastal areas. It is also an excellent fuel wood and is among the hottest burning fuel woods in the world.
It is also frequently planted as a windbreak and to stabilise coastal sand dunes.