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close this book Nitrogen Fixing Trees highlights
View the document Acacia koa - Hawaii's most valued native tree
View the document Acacia leucophloea - shade and fodder for livestock in arid environments
View the document Alnus acuminata: valuable timber tree for tropical highlands
View the document Albizia saman: pasture improvement, shade, timber and more
View the document Casuarina junghuhniana: a highly adaptable tropical casuarina
View the document Enterolobium cyclocarpum: the ear pod tree for fasture, fodder and wood
View the document Erythrina variegata: more than a pretty tree
View the document Inga edulis: a tree for acid soils in the humid tropics
View the document Pithecellobium dulce - sweet and thorny
View the document Pterocarpus indicus - the majestic n-fixing tree
View the document Robinia pseudoacacia: temperate legume tree with worldwide potential
View the document Acacia nilotica - pioneer for dry lands
View the document Acacia saligna - for dryland fodder and soil stabilization
View the document Acacia senegal: gum tree with promise for agroforestry
View the document Acacia seyal - multipurpose tree of the Sahara desert
View the document Acacia tortilis: fodder tree for desert sands
View the document Alnus nepalensis: a multipurpose tree for the tropical highlands
View the document Casuarina equisetifolia: an old-timer with a new future
View the document Casuarina glauca: a hardy tree with many attributes
View the document Chamaecytisus palmensis: hardy, productive fodder shrub
View the document Dalbergia latifolia: the high-valued Indian rosewood
View the document Dalbergia melanoxylon: valuable wood from a neglected tree
View the document Erythrina edulis: multipurpose tree for the tropical highlands
View the document Erythrina sandwicensis - unique Hawaiian NFT
View the document Hippophaë rhamnoides: an NFT valued for centuries
View the document Leucaena diversifolia - fast growing highland NFT species
View the document Leucaena: an important multipurpose tree
View the document Olneya tesota - a potential food crop for hot arid zones
View the document Honey mesquite: a multipurpose tree for arid lands
View the document Pongamia pinnata - a nitrogen fixing tree for oilseed
View the document Guazuma ulmifolia: widely adapted tree for fodder and moreli
View the document Faidherbia albida - inverted phenology supports dryzone agroforestry
View the document Gleditsia triacanthos - honeylocust, widely adapted temperate zone fodder tree
View the document Andira inermis: more than a beautiful ornamental tree
View the document Erythrina poeppigiana: shade tree gains new perspectives
View the document Albizia procera - white siris for reforestation and agroforestry
View the document Albizia odoratissima - tea shade tree
View the document Adenanthera pavonina: an underutlized tree of the humid tropics
View the document Acacia mangium: an important multipurpose tree for the tropic lowlands
View the document Acacia auiculiformis - a multipurpose tropical wattle
View the document Pentaclethra microphylla: a multipurpose tree from Africa lwith potential for agroforestry in the tropics
View the document Myroxylon balsam and much more
View the document Ougeinia dalbergioides: a multipurpose tree for sub-tropical and tropical mountain regions
View the document Prosopis alba and prosopis chilensis: subtropical semiarid fuel and fodder trees
View the document Sesbania sesban: widely distributed multipurpose NFT
View the document Prosopis cineraria: a multipurpose tree for arid areas
View the document Juliflorae acacias: new food source for the sahel
View the document Sesbania grandiflora: NFT for beauty, food, fodder and soil improvement
View the document Acacia aneura - a desert fodder tree

Casuarina glauca: a hardy tree with many attributes


Known as swamp she-oak in its native Australia, Casuarina glauca grows in difficult, saline sites inhospitable to many other trees. This casuarina has been planted in agroforestry systems primarily as a windbreak but also in woodlots for fuelwood and reserve fodder.



Casuarina glauca Sieb. ex Spreng. (family Casuarinaceae) is a medium-sized tree 10-15 m tall, occasionally reaching 25 m, with an often buttressed and fluted main stem. The dense crowns of plantationgrown trees become sparse to narrow in free-growing trees (Midgley et al. 1983). The jointed, green. cylindrical branchlets, which serve as leaves for casuarinas, are much coarser, thicker, and longer (1 mm diameter, 30-60 cm long) than those of C. equisetifolia or C. cunninghamiana The length of the internodes on branchlets averages 15 mm. The reduced, true leaves appear as teeth at the nodes and vary in number from 12-16, occasionally to 20.

C. glauca is dioecious; male and female trees occur in approximately 1:1 ratios in natural stands. Male flowers appear as 4-7 cm long, light-green spikes. Female flowers are small, dark red, and inconspicuous. Males trees flower at 2-3 years of age and female trees produce fruits one year later. Trees fruit mainly in autumn, except in plantations (for example, in Egypt), where trees produce crops in both autumn and spring.

The cone-like woody fruits vary in size with provenance, ranging from 12 to 16 mm long and 11.5 to 14 mm wide (ElLakany and Youness 1985). Fruit bracteoles are relatively thin compared to other casuarinas. C glauca is a prolific cone producer and averages 70 seeds/cone and 1,300,000 seeds/kg (El-Lakany et al. 1989). Closed cones may persist on the tree for more than a year.

Casuarina glauca hybridizes with other Casuarina species through open, wind pollination. A hybrid with C cunninghamiana has been reported in Australia and identified in Egypt (Badran et al. 1976), and a hybrid with C equisetifolia is recognized in USA and Egypt.



Natural distribution is limited to a narrow coastal belt of southeast Australia (23-37° S latitude) with an insular occurrence on Fraser Island. Trees occasionally extend 50-80 km inland. Trees often occur along the edges of tidal reaches and estuaries, intermediary between mangrove swamps and open woodland, and sometimes on or near beach fronts. On swampy sites water tables may be only 30 cm from the surface. Trees usually occur close to sea level but are also found on seasonally moist hillsides near the sea, and up to 900 m elevation in Hawaii. In its native range annual precipitation averages 500 mm; in Hawaii rainfall is as much as 4,000 mm (NAS 1984). Annual temperatures range from 5 to 33°C.

C glauca is more salt tolerant than other casuarinas (ElLakany and Luard 1983). Seedlings outgrew eight species in nutrient solutions containing increasing concentrations of NaCl. In these tests both C glauca and the closely related C obesa survived 500 mM/l NaCl-a level close to 3/4 the total salinity of seawater.

C glauca has proven widely adaptable. In Egypt, trees grow on clay to coarse sand, saline to calcareous, and dry to waterlogged soils. Trees grow on very dry sites with saline soils in Israel and flourish on limestone soils in Florida USA. In Hawaii, trees have been planted on parent basalt. C glauca has also been successfully planted in Kenya India Malawi. and South Africa.



No seed pretreatment is required. Turnbull and Martensz(1982) recommend temperatures of 20-25°C and El-Lakany and Shepherd (1983) recommend 30°C to germinate C. glauca seed. Seed stores well up to eight months at room temperature (El-Lakany et al. 1990). Seed for experimental purposes is available from the Australian Tree Seed Centre, (Div. Forestry and Forest Products, CSIRO, Canberra Australia), the Desert Development Center (AUC, P.O. Box 2511, Cairo, Egypt), and NFTA.

Wide intraspecific variation for certain characteristics has been reported for C. glauca (El-Lakany and Shepherd 1983). Early results of provenance trials in Egypt and elsewhere suggest substantial growth gains are possible through use of proper seed sources. In an irrigated plantation on the desert fringes in Egypt, height growth varied by a factor of two among nine provenances (ElLakany and Youness 1985). Biomass productivity of 12year-old irrigated plantations was estimated at 496 t/ha of which wood volume was 294 m³/ha (Megahed and ElLakany 1986). Provenance testing is underway in California, USA for frost colerance (Merwin 1990). Irrigation is required to establish trees in desert areas.



C glauca forms a symbiosis with actinomycetes of the genus Frankia. Spherical woody nodules, some exceeding 20 cm in diameter, are found in large masses near the base of the trunk and as deep as 10 m. Root nodules have been observed on trees in natural stands and on trees in plantations growing on very saline or waterlogged sites. The greatest number of nodules are found in soils with pH ranging from 6-8.

For Casuarina species, N-fixation is greatest when species are inoculated and when inoculated with nodules from the same species (Reddell and Bowen 1985, Reddell 1990). Crushed nodules or soil from beneath mature trees can be used to inoculate nursery seedlings. Under conditions of high soil salinity, drought or waterlogging, C. glauca exhibited more efficient N-fixation than C cunninghamiana (El-Lakany 1987). Inoculum is available from CSIRO, Davies Lab, PMB, Aikenvale, QLD 4814, Australia.




C glauca finds its best use in shelterbelts, windbreaks, and amenity plantings around settlements. The trees are wind-firm and show rapid early growth. In parts of North Africa and the Middle East, especially in water-scarce areas, they are preferred to eucalypts for plantings. Windbreaks are planted 2-3 rows wide. Like other casuarinas, trees can be coppiced to form dense hedges. The low branching habit and extensive litter production help reduce soil erosion. Trees have also been used successfully to stabilize stream banks and shifting sand dunes.



The most universal use of casuarina is for fuel. The wood has a high calorific value (about 5,000 Kcal/kg) and tends to burn slowly with little smoke or ash. Branches, branchlets, and other litter also burn well. Casuarina wood makes excellent charcoal. Wood is reddish-brown, tough, and fissile with a density ranging from 662 El-Lakany 1983) to 980 (Midgley et se. 1983) kg/m³. Timber is used for handles, fence rails, rafters, shingles, stakes, small sea-water piles, for flooring and turnery, and in Egypt, with some technical difficulty, for particle board. The timber does not season readily and has a tendency to warp.


Other Uses:

Cattle, sheep and goats will graze C glauca seedlings, suckers. and branchlets. The ground foliage has been included as an ingredient in chicken feed (El-Deek et al. 1988). Foliage contains 9% crude protein, 37% crude fiber, and 37% total digestible nutrients (Omran and Nour 1980).

C glauca has potential for use in wide-row intercropping and, contrary to common belief, has been found to increase yields of crops sheltered (El-Sayed et se. 1983). Farmers usually dig a ditch between the crop and trees to minimize competition for water and nutrients. An excellent shade tree, it is planted along streets in many arid zone cities. Like other casuarinas, the dense canopy and slow-todecompose litter severely inhibit understory plant growth.



Prolific production of root suckers lends C glauca a serious potential for weediness, especially in humid areas. It is considered a pest in Florida and the Hawaiian isles (NAS 1984). In arid areas such as Egypt it has generally not become a weed, although it can spread along water courses. The tree itself is almost pestfree except for Stromatium fulvum, a wood borer which makes the stem susceptible to wind-damage and rot.



El-Lakany, M.H. and K.R. Shepherd. 1983. Variation in seed germinability, seedling growth, and biomass between provenances of Casuarina cunninghamiana Miq. and C. glauca Siev. Forest Management and Ecology 6:201-216.

El-Lakany M.H., J.W. Turnbull, and J.L. Brewbaker (eds). 1990. Advances in Casuarina research and utilization. Proc. 2nd Internal. Casuarina Workshop, Jan. 15-20, 1990, Desert Development Ctr., Cairo, Egypt.

El-Sayad, A..B., T.A. Omran, and A.E. Khalil. 1983. Influence of windbreaks on crop yields in West Nubariah region. Alex. Sci. Exch. 4:57-71.

Megahed, M.H. and M.H. El-Lakany 1986. Biomass charac teristics of young Casuarina plantations in northwestern region of Egypt. Alex J. Agric. Res. 31:411422.

Midgley, S.J., J.W. Turnbull, and R.D. Johnston (eds). 1983. Casuarina ecology, management, and utilization. Proceedings of an international workshop, Canberra, Australia. CSIRO, Melbourne. 286 p.

NAS (National Academy of Sciences). 1984. Casuarinas: Nitrogen-fixing trees for adverse sites. Innovations in tropical reforestation. National Academy Press, Washington, D.C. 118 p.

Reddell, P. and G.D. Bowen. 1985. Frankia source affects growth, nodulation and nitrogen fixation in Casuarina species. New Phytol. 100:115-122.

Turnbull, J.W. and P.N. Marten=. 1982. Seed production, collection and germination in Casuarinaceae. Austr. For. Res. 12:281-294.

A full list of references is available from NFTA.


NFTA 93-03 June 1993