Casuarina junghuhniana (Casuarinaceae) in India R. S. C. Jayaraj Institute of Forest Genetics and Tree Breeding, PO Box 1061, R.S. Puram, Coimbatore 641 002, India. Email: jayaraj@icfre.org Abstract. Casuarina junghuhniana Miq., introduced into India in 1996, is gaining importance as an agroforestry species, with potential use in pulp and paper industry. Tree improvement of the species and attempts at clonal forestry are in progress. A hybrid of Casuarina equisetifolia L. and C. junghuhniana, introduced in 1951 from Thailand, is also planted in India, with the wrong identity as Casuarina junghuhniana. The present paper reviews the silviculture and tree improvement of the species, especially the attempts at introduction to various parts of the world by CSIRO, Australia, with special reference to India. The paper also attempts to resolve the confusion between the hybrid and the pure species, among the planting agencies in India. Introduction Casuarina junghuhniana Miq. (=Casuarina montana Leschen ex Miq.), named after Friedrich Franz Wilhelm Junghuhn (1809–1864), a German botanist who conducted extensive studies on the land and people of Java, is a native of the highlands of eastern Indonesia – East Java, Bali and the Lesser Sunda Islands – where it occurs as pure stands on mountain summits. It is commonly known as jemera in Indonesia, cemera gunung in Java, Kasuarin in Timor, Son pradiphat in Thailand, Shan di mu ma huang in China, and as red-tipped ru or mountain ru or mountain she-oak in English. Natural distribution Casuarina junghuhniana naturally occurs in the climax montane rainforest of Bali, as an associate of species such as Podocarpus imbricatus, Crypteronia paniculata, Eugenia sp., Dysoxylum sp., Laplacea sp., Magnolia blumei and Ficus sp. (Robinson et al. 1982). In the Lesser Sundas, it occurs as pure forests at elevations from 2100 to 2700 m, above the mixed montane forests. Here, the practice since prehistoric times of setting fire to clear undergrowth and to encourage growth of new forage to attract game, has led to proliferation of fire-resistant trees such as C. junghuhniana as pure stands. In Timor and Wetar Island, this species is seen as a part of savanna and grows as pure stands in cleared areas (Wikramanayake et al. 2001). Subsp. junghuhniana typically grows in pure stands on volcanic slopes at altitudes of 1500–3100 m, and can also occur below 100 m. Subsp. timorensis is normally found at lower altitudes, from sea level to 300 m, especially in Timor. Taxonomy It has been suggested that the taxonomy of the species needs revision. At present, the C. junghuhniana consists of two subspecies, namely subsp. junghuhniana found in the islands of Java, Bali, Lombok, Sumbawa and Flores and subsp. timorensis found in Timor, Wetar, Sumba and perhaps Sumbawa, Indonesia. There are variations within the subspecies. The subsp. junghuhniana has discrete populations, with coarse-, fine- and intermediate-textured deciduous branchlets. The coarse form has rugged, deeply furrowed corky bark, unusual for Casuarina. The subsp. timorensis also has two forms, called locally as the ‘white’ and ‘black’ casuarinas. The hillside form has robust deciduous branchlets whereas the riverine form has short and thin branchlets (Pinyopusarerk and Boland 1995). Morphometric analysis and molecular genetic studies of three species of Casuarina and two species of Allocasuarina has placed C. junghuhniana with A. huegeliana, rather than with other species of Casuarina, suggesting requirement of a more intensive research to ascertain the distinction between the two species (Kamalakannan et al. 2006). Genetic variation A study of genetic variation and population structure of 113 individuals from 13 international provenances, by using inter-simple sequence repeats (ISSR), revealed significant genetic variation and low levels of gene flow among the 10 native provenances because of geographical isolation. The introduced and cultivated provenances (landraces) in Kenya and Tanzania had low genetic differentiation, perhaps owing to co- ancestry. The study revealed that these cultivated provenances might have originated from the native provenances of East Java, Lombok, Bali and Sumbawa (Ho et al. 2004). Silviculture Casuarina junghuhniana is a pioneer species in revegetation of deforested grasslands, volcanic ash, gravelly stream beds and rocky slopes. In its native habitat it is found from sea level up to an altitude of 3100 m (Pinyopusarerk and House 1993). Rainfall in its natural habitat is in the range of 700–1500 mm. The species grows in a variety of soils from volcanic to sandy to CSIRO PUBLISHING www.publish.csiro.au/journals/ajb Australian Journal of Botany, 2010, 58, 149–156 Ó CSIRO 2010 10.1071/BT09210 0067-1924/10/020149