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Casuarina equisetifolia
Australian pine
Australian pine, beach she-oak, ironwood (Eng); pino marítimo, casuarina blanca (Spa).
Non-Native
DID YOU KNOW...? This she-oak is often used to form screens to protect against the wind and salt from the sea. One example of this is the extensive grove of Australian pines planted in the environs of Gran Canaria airport.
DESCRIPTION
Evergreen tree, with a sparse, generally pyramidal crown. The branches are erect or a little pendulous so that, from a distance, it looks like a pine. In the Canary Islands it reaches a height of 10-15 m, but in other places can be up to 40 m tall. The trunk is straight and has greyish-brown bark that is rough and cracked. What at first seem to be needles (leaves) are in fact very thin twigs that hang down and are greyish green in colour. The true leaves are tiny scales arranged in a ring around the knots of the twigs. It has unisexual flowers that are borne on the same plant (a monoecious species), differentiating it from Casuarina cunninghamiana, which is dioecious. When the female flowers are fertilised they form fruits that look like elongated, globose cones. These are about 1 cm in diameter and formed by a group of bracts. When separated, they release numerous tiny, light, winged seeds that are dispersed by the wind. Casuarina equisetifolia can also be distinguished from Casuarina cunninghamiana by having fewer scales in each ring (6-8) and larger seeds (up to 7 mm).
ECOLOGY
This species lives naturally in barren, semi-arid areas in tropical and subtropical zones, in sandy soils, and salt-rich environments close to the coast. It is undemanding and withstands strong winds, prolonged droughts, and proximity to the sea. Although it prefers well-drained sandy substrates, this tree adapts to any soil type, even when poor and full of debris. In the Canary Islands it grows in coastal zones and along the lower edge of the piso basal lowlands.
DISTRIBUTION
It comes from the north and northeast of Australia, Southeast Asia (from Burma to Vietnam), Melanesia and Polynesia. As a cultivated species, it is widespread across the Canary Islands, and has become established in the wild in Tenerife, Gran Canaria and Fuerteventura.
