Casuarina oligodon

Casuarina oligodon is an evergreen tree from New Guinea. It belongs to the Casuarinaceae family. Its common names include she-oak and kilu. It grows in wet tropical highlands, along rivers and on ridges. There, it can form large stands of its own kind. Its habitat reaches about 8,200 feet [2,500 metres], and sometimes higher. People have long grown it in Papua New Guinea's highlands. Moving seedlings may have helped spread it within that region.

Garden references give a height and spread of 82 feet [25 metres]. Other accounts place its maximum height near 98 feet [30 metres]. Its growth rate is moderate. Slender, branching twigs give the tree its green to grey-green foliage. The true leaves are tiny scales set in whorls. Wind carries pollen between its flowers. The supplied sources give no flowering season or fruit description. They also give no clear account of its bark.

This tree needs sun and does not grow in shade. It prefers moist soil that drains well. It accepts sand, loam, and clay. Wild trees often grow in sand beside streams and rivers. Slightly acid soil suits it best, though it tolerates a wider pH range. Its home climate has high humidity through the year. Annual rain there totals about 75–102 inches. The weak dry season lasts no more than two months. PFAF lists USDA zones 10–12, which places it in warm-climate gardens.

Its main value lies in wood production and land care. People use its hard, heavy wood for fuel and charcoal. They also use it for fences, poles, houses, and general building work. Growers plant it for shade in plantations and as shelterbelts. Its wide root system helps hold soil on steep slopes. Fallen foliage covers bare ground and helps limit soil loss. The tree fixes nitrogen and helps restore soil fertility. In Papua New Guinea, people plant it to restore highland grasslands. It can compete with strong grasses at these sites.

Growers raise new trees from seed in nursery beds. Sprouting can begin after about ten days, but seed viability is low. Young plants move into nursery tubes before final planting. The supplied sources name no specific pests or diseases. PFAF reports no weed potential. Both plant references report no known hazards. That does not establish safety for every person or animal. PFAF lists no known food or medicinal uses.