Casuarina equisetifolia Forst. & Forst. (syn. C. litorea L.), is probably the most widespread and well-known member of the household Casuarinaceae, and has many names: Casuarina, ironwood, coast she-oak, horsetail, Australian pine, whistling pine, beefwood, agoho (Philippines), ru (Malaysia), filao (Vietnam, West Africa, West Indies) and nokonoko (Fiji). All of the casuarinas are nitrogen fixing. Casuarinas assist an actinorhiza symbiont of their root nodules, versus the rhizobium symbiont discovered within the root nodules of leguminous bushes that repair N2.
C. equisetifolia has two variants. C. equisetifolia var. incana is a small (6-10 m) tree that grows completely alongside the coast of Queensland and northern New South Wales. Var. equisetifolia is a tall (10-40 m) tree discovered on seacoasts from Malaysia to subtropical Australia, Melanesia, Micronesia, the Philippines and Polynesia.
Like different Casuarinaceae, C. equisetifolia as a conifer-like look which is elevated by hanging inexperienced branchlets and cone-like fruits. Casuarinas are literally typical angiosperms with simplified and diminished unisexual flowers. They’re dioecious or monoecious, the proportion of male, feminine and monoecious bushes various broadly from one web site to a different. The stem of Casuarinaceae consists of two components: indeterminate persistent branches which, after secondary thickening, kind the everlasting above-ground plant body-, and determinate deciduous branchlets (incorrectly known as cladodes), about 1.5-2.5 mm in diameter. These branchlets are the key photosynthetic organs of the plant (Torrey and Berg 1988). The leaves are diminished to white or brown scales fused laterally on the base in whorls that outline nodes on the branchlets.
Particular person vegetation have putting phenotypic variations within the crown form, department angle, size of branchlets, and dimension and form of cones. C. equisetifolia is thought to hybridize with different casuarinas, comparable to C. junghuhniana and C. glauca.
Casuarina equisetifolia is illiberal of frost. Var. incana thrives within the heat subhumid zone whereas var. equisetifolia is a heat-loving plant of the recent subhumid zone. Though C. equisetifolia is mostly a lowland tree, it grows at altitudes as much as about 600 m in Hawaii.
C. equisetifolia tolerates a variety of moisture availability. C. equisetifolia grows greatest alongside the coast, the place sea spray dietary supplements moisture from the water desk in arid and semi-arid climates with common annual rainfall USES. The wooden of C. equisetifolia is darkish brown, very exhausting (density 1000 kg/m3), and immune to decomposition in soil or saltwater. It’s typically used as spherical wooden for making piles, poles and fences, however splits too severely throughout drying to be standard as lumber; though in areas with acute wooden shortages, comparable to southeastern China, C. equisetifolia is used for home beams and easy furnishings (Midgley et al. 1983).
Due to its excessive calorific worth (ca. 5000 kcal/kg), C equisetifolia wooden is a superb supply of gasoline and charcoal. Individuals in China and India use stumps and even litter for gasoline, use which additionally attracts closely on soil phosphorus and potassium reserves.
Due to its resistance to salt-laden winds, C. equisetifolia is broadly used to stabilize coastal sand dunes. It’s also extensively planted as windbreaks to guard crops. In some tropical lowland agroforestry methods it’s related to crops comparable to espresso, cashew nut, coconut, groundnut, sesame and varied grain legumes.
C. equisetifolia and its hybrids are sometimes used as decorative vegetation for city beautification, parks and seaside resorts. There may be additionally potential for incorporating C. equisetifolia into mixed-species tree plantations.
ROOT SYMBIOSES. Root nodules are prolific on C. equisetifolia once they happen. Efficient strains of Frankia at the moment are out there to inoculate C. equisetifolia on websites the place the identical Frankia-compatible group of bushes (in precept any species of the Casuarina genus) haven’t been beforehand planted.
When there are not any limiting components, the response to inoculation is spectacular. Inoculation with Frankia entrapped in alginate beads is probably the most handy system (Sougoufara et al. 1989). Inoculation with crushed nodules, which is usually practiced, needs to be discouraged due to the chance of introducing non-nodulating or poorly efficient strains and disseminating soil-borne pathogens Pseudomonas salanacearum, a bacterium that causes casuarina wilt. Extended waterlogging inhibits nodule growth.
As in different actinorhizal vegetation, spontaneous endomycorrhizal (VAM) an infection happens simply in C. equisetifolia. True ectomycorrhizae have, nonetheless, been seldom reported, besides in sure coastal areas of northern Australia the place a variety of fungi are concerned (Paul Reddell, pers. comm.). Proteoid roots have additionally been noticed on their root methods. These are distinctive constructions manufactured from tightly packed rows of rootlets which can improve the power of the host plant to soak up vitamins and thereby higher tolerate nutrient poor soils.
SILVICULTURE. Ripe inexperienced cones are collected from branches lopped from mature bushes and dried within the solar. One kg of inexperienced cones yields 20-60 g of seeds. There are 300,000-700,000 cleaned seeds/kg. The seeds have a comparatively low viability of 80-90% for recent seeds and 30-40% for seeds after three years storage. Germination is normally full inside 2 weeks after planting.
At 6-10 weeks the 10-15 cm excessive seedlings are transplanted into containers the place they’re grown for 5-Eight months to a peak of 50-70 cm, at which period they’re transplanted to the sphere. One other process is to transplant the- 10-15 cm seedlings into a brand new mattress at a 10 x 10 cm spacing to acquire vegetation able to be planted naked rooted within the discipline. Cuttings and microcuttings can be utilized when working with clones.
C. equisetifolia doesn’t sucker as vigorously as C. glauca. Plantation planting density is normally round 2,000 vegetation/ha, however non-public farmers can plant as much as 8,000 to 10,000 bushes/ha (Midgley et al. 1983).
C. equisetifolia will be improved by exploiting the massive phenotypic variation of its populations. There are primarily two approaches to extend each wooden manufacturing and N2-fixation potential: typical plant breeding and screening of elite people adopted by vegetative propagation.
The N2-fixing potential of C. equisetifolia will be enormously enhanced by way of using chosen clones inoculated with efficient Frankia strains. Clone beta of C. equisetifolia, inoculated with pressure ORS021001 and irrigated all through the dry season in Senegal, mounted 45 g N2/yr/tree through the two first years of progress (Dommergues, unpublished information). Extrapolating this consequence offers a determine of 90 kg of N2 mounted yearly/ha at a planting density of two,000 bushes/ha.
YIELD. In comparison with a number of the different casuarinas, C. equisetifolia is comparatively short-lived, surviving solely 40-50 years. Its progress is fast through the first 7 years (1.5-2.5 m/yr), then progressively declines. Generally, the amount yield reaches a most at age 15-20 years (7-10 m3 /ha yr -1). The yield may in all probability be enormously elevated through the use of chosen clones and making use of correct administration practices, together with irrigation and inoculation with efficient Frankia strains. C. equisetifolia plantations are usually managed on a rotation of 7-15 years.
PESTS AND DISEASES: C. equisetifolia isn’t susceptible to any severe pest and illnesses, besides when grown in unfavorable situations. Pests that assault the tree embody crickets and grasshoppers (Chondracis rosea, Schistocera gregaria), defoliators (Lymantria xylina), stem borers (Apate momachus) and sap feeders (Icerya spp.). The most important root illnesses are attributable to, Pseudomonas solanacearum, Trichosporium vesiculorum and Rhizoctonia spp.
Midgley, S.J., J.W. Turnbull and R.D. Johnston (eds). 1983. Casuarina Ecology, Administration and Utilization. CSIRO, Melbourne.
Sougoufara, B., H.G. Diem and Y.R. Dommergues. 1989. Response of field-grown Casuarina equisetifolia to inoculation with Frankia pressure ORS021001 entrapped in alginate beads. Plant and Soil 118:133- 137.
Torrey, J.G. and R.H. Berg. 1988. Some morphological options for generic characterization among the many Casuarinaceae. Amer. J. Bot. 75:864-874.
Written by Dr. Y. Dommergues, ORSTOM / CTFT, 45bis Avenue de la Belle Gabrielle, 94736 Nogent-sur-Marne, Cedex, France.
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