3077

11: Auxiliary plants

Casuarina oligodon L.A.S. Johnson

CASUARINACEAE

Papua New Guinea: yar, soft yar.

Occurring naturally in the highlands of New Guinea, also cultivated.

Commonly grown for fuelwood, charcoal, posts and small size timber. Casuarina oligodon is strongly self-regenerating and is used in reforesting grasslands in the highlands of Papua New Guinea as it competes well with grasses such as Imperata cylindrica (L.) Raeuschel, Saccharum robustum Brandes & Jeswiet ex Grassl. and Themeda australis (R. Br.) Stapf. It is also planted as a shade tree in coffee plantations.

Medium to tall tree, up to 30 m tall, trunk up to 60 cm in diameter. Bark grey-brown. Twigs needle-like, drooping, grooved; leaves reduced to 6 minute scales arranged in whorls. Male flowers in spikes at end of branchlets, consisting of 1 stamen surrounded by 4 scales; female flowers in ovoid heads. Fruit a small samara held in a woody cone less than 1 cm in diameter. Casuarina oligodon fixes atmospheric nitrogen. It occurs at 1500—1800 m altitude where annual rainfall ranges from 1900—2600(—5000) mm and relative humidity is permanently high. It is mainly found on sandy soils along creeks, but grows well on many soils, unless poor or leached. Boron deficiency causes stunting. Propagation is mainly by seed, no root suckers arise, but epicormic shoots are produced after damage e.g. by fire. Branches are easily damaged by strong wind.

[108]Midgley, S.J., Turnbull, J.W. & Johnston, R.D. (Editors), 1983. Casuarina ecology, management and utilization. Proceedings of an international workshop, Canberra, Australia, 17–21 August, 1981. Commonwealth Scientific and Industrial Research Organization, Melbourne, Australia. 286 pp.
[117]National Research Council, 1984. Casuarinas: nitrogen-fixing trees for adverse sites. Innovations in tropical reforestation. National Academy Press, Washington, D.C., United States. 118 pp.

M.S.M. Sosef & L.J.G. van der Maesen

Sosef, M.S.M. & van der Maesen, L.J.G., 1997. Casuarina oligodon L.A.S. Johnson. In: Faridah Hanum, I & van der Maesen, L.J.G. (Editors): Plant Resources of South-East Asia No 11: Auxiliary plants. PROSEA Foundation, Bogor, Indonesia. Database record: prota4u.org/prosea