Casuarina equisetifolia
beach sheoak
Overview
Casuarina equisetifolia is an evergreen tree reaching 20-35 m (66-115 ft) tall with a trunk to about 50 cm (20 in) in diameter and an open, often weeping crown. What appear to be needle-like leaves are slender green photosynthetic branchlets (cladodes) 10-30 cm (4-12 in) long and roughly 0.5-1 mm wide, jointed into segments; the true leaves are reduced to rings of 6-8 minute scale teeth at each joint. The bark is grey-brown and finely fissured. The species is monoecious or dioecious: male flowers form brownish spikes at branchlet tips, while female flowers occur in small reddish clusters along the branches. Fertilised female flowers develop into woody cone-like fruiting structures 10-24 mm (0.4-0.9 in) long containing winged seeds 6-8 mm long. Growth is rapid, often 1-2 m (3-7 ft) per year on suitable coastal sites, and roots fix atmospheric nitrogen through nodules associated with Frankia spp. actinobacteria. The wood is hard and dense. The species tolerates salt spray, sandy soils, and periodic inundation, but is frost-sensitive and can spread beyond its native range, forming dense stands that suppress understorey vegetation and alter beach nesting habitat.
Native Range
Native to coastal regions of the Indo-Pacific, from eastern Africa and South and Southeast Asia through northern and eastern Australia to Polynesia. It grows on foredunes, sandy beaches, and behind mangroves, usually within a few hundred metres of the sea at elevations below about 100 m (330 ft).Suggested Uses
Planted for coastal windbreaks, dune stabilisation, and shade in tropical and subtropical seaside areas, spaced 3-5 m (10-16 ft) apart for screens. The hard, dense wood is used for fuel and small timber. Outside its native range it spreads into beach and dune systems and is managed as an environmental weed.How to Identify
Appearance
Size & Dimensions
Height66' - 115'
Width/Spread20' - 30'
Reaches mature size in approximately 10 years
Colors
Bloom Information
Flowers mainly in autumn and spring, with scattered flowering through much of the year in tropical climates. Male trees turn rust-brown as branchlet tips release pollen over 2-4 weeks, and wind carries the pollen to the small red female flowers. Cones mature 4-6 months after pollination.
Detailed Descriptions
Flower Description
brown (male) and red (female)Foliage Description
grey-greenGrowing Conditions
Sun Requirements
Requires 6-12 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight