Related Links
Local names:
Bengali (chandan,sufaid-chandan,peetchandan,srikhanda), Burmese (santagu), English (sandal,cendana,sandal tree,East Indian sandalwood,white Indian sandalwood,sandalwood), French (Santal blanc), German (Weisser Sandel(holz)ßaum), Gujarati (sukhad,sukhet),
Santalum album is a small evergreen tree that grows to 4 m in Australia, but in India it is much larger and can grow to a height of 20 m; girth of up to 2.4 m, with slender drooping branchlets. Bark is tight, dark brown, reddish, dark grey or nearly black, smooth in young trees, rough with deep vertical cracks in older trees, red inside. Leaves thin, usually opposite, ovate or ovate elliptical, 3-8 x 3-5 cm, glabrous and shining green above, glaucous and slightly paler beneath; tip rounded or pointed; stalk grooved, 5-15 cm long; venation noticeably reticulate. Flowers purplish-brown, small, straw coloured, reddish, green or violet, about 4-6 mm long, up to 6 in small terminal or axillary clusters, unscented in axillary or terminal, paniculate cymes. Fruit a globose, fleshy drupe; red, purple to black when ripe, about 1 cm in diameter, with hard ribbed endocarp and crowned with a scar, almost stalkless, smooth, single seeded. The generic name is derived from the Greek ‘santalon’ meaning ‘sandalwood’, and the species name from the Latin ‘albus’ meaning ‘white’, in allusion to the bark.
Ecology
S. album is indigenous to the tropical belt of the Indian peninsula, eastern Indonesia and northern Australia. There is still debate as to whether S. album is endemic to Australia or was introduced by fishermen or birds from eastern Indonesia centuries ago. The main distribution is in the drier tropical regions of India and the Indonesian islands of Timor and Sumba. The principal sandal tracts are most parts of Karnataka and adjoining districts of Maharashtra, Tamil Nadu and Andhra Pradesh in India. The species is mostly found in dry deciduous and scrub forests in this region. The vegetation type is a typical monsoon vine thicket growing on pure sand. It has been recorded on coastal sand dunes immediately above the normal high water mark and close to the mangroves. It also grows on low lateritic cliffs above the beach. It is a partial parasite that attaches to the roots of other trees, it needs ‘nurse’ species in the area of planting out. Host plants that fix nitrogen and provide light shade are preferred. Senna siamea is good for this, and a most probable natural host is Drypetes lasiogyna, observed to be the most prolific species in the vicinity of S. album. It does not tolerate frost or waterlogging, but is drought-hardy and is a light demander in sapling and later stages. Prolonged drought and fire kill trees.
Native range
Australia, India, Indonesia
Tree management
The yield of the heartwood varies according to age and locality. As a rule of thumb, each tree adds 1 kg of heartwood to its weight each year after the age of 15 years. On deep rich soils in moist areas, trees grow luxuriantly but the heartwood formation is slow and the oil content is low, while the slower-growing trees on difficult sites at elevations between 600-900 m and in rainfall zones of 500-1 000 mm develop maximum heartwood with high oil content. Girth increments for S. album in India are 1-1.3 cm/year in natural stands and up to 5 cm annually in cultivated areas. Between-tree variation in heartwood content and oil yields is high, indicating considerable scope for selection and breeding. Seedlings require protection from wild animals and cattle; nurse bushes provide such protection, and also protect them from excessive heat of the sun, which can kill the tender seedlings in the hot summer months. It is desirable not to clean-weed all round the sandal seedlings, as the roots form haustorial connections with adjoining weed growth. Spacing adopted for raising pure plantations is 3 x 3 - 5 x 5 m. Plantations should strictly be protected from fire. Trees attain exploitable stage (over 15 cm diameter at breast height) in about 30 years, yielding about 50 kg of heartwood, and attain 25 cm dbh in 40 years; such a well-grown tree, including the roots, can yield over 250 kg of scented heartwood. Young sandal trees coppice well. Whole tree harvesting is employed, and both living and dead trees are utilized.
Good seed is reported from trees over 20 years of age. Seed storage behaviour is orthodox; no loss in viability after 2 years storage at room temperature (seed longevity declines rapidly at room temperature); viability is reduced from 90-15% after 3 years storage at 7 deg. C with 30-45% r.h. Seeds tolerate desiccation to 2% mc, and no loss in viability is observed after 16 months hermetic storage at 4 deg. C with 3-10% mc. On average there are 4 300-6 800 seeds/kg.
S. album is indigenous to the tropical belt of the Indian peninsula, eastern Indonesia and northern Australia. There is still debate as to whether S. album is endemic to Australia or was introduced by fishermen or birds from eastern Indonesia centuries ago. The main distribution is in the drier tropical regions of India and the Indonesian islands of Timor and Sumba. The principal sandal tracts are most parts of Karnataka and adjoining districts of Maharashtra, Tamil Nadu and Andhra Pradesh in India. The species is mostly found in dry deciduous and scrub forests in this region. The vegetation type is a typical monsoon vine thicket growing on pure sand. It has been recorded on coastal sand dunes immediately above the normal high water mark and close to the mangroves. It also grows on low lateritic cliffs above the beach. It is a partial parasite that attaches to the roots of other trees, it needs ‘nurse’ species in the area of planting out. Host plants that fix nitrogen and provide light shade are preferred. Senna siamea is good for this, and a most probable natural host is Drypetes lasiogyna, observed to be the most prolific species in the vicinity of S. album. It does not tolerate frost or waterlogging, but is drought-hardy and is a light demander in sapling and later stages. Prolonged drought and fire kill trees.
Most natural seedlings of sandal are found growing in the middle of thorny bushes, where the birds have dropped the seeds. Artificial propagation is easily done by directly dibbling freshly collected ripe seeds in worked up soil patches, with the onset of the monsoon, in the middle of the nurse bushes or in protected patches. Fresh seed has a dormancy period of 2 months. Manual scarification or gibberellic acid can break this. They germinate in about 8-14 days, with a germination rate of 70%. Lantana camara, commonly found growing in scrub forests in areas suitable for sandal, acts as a good nurse to the seedlings in the early stages. Planting of container-raised seedlings or branch cuttings is also successful; trees are raised with a host plant, for example Cajanus cajan, Senna siamea, Terminalia, Lagerstroemia, Anogeissus, Dalbergia, Pongamia, Albizia and Acacia species. Seeds can be sown in polythene bags along with the sandal seeds and watering is once a day. Sandal seedlings attain a height of 15-20 cm by planting time and are planted out in the field along with the host plant. Seedling growth is rapid with 20-30 cm obtained at the end of the 1st year and 60-70 cm at the end of the 2nd year. Root suckers are produced when roots are exposed or injured. The nursery phase to raise sturdy 30 cm plants is usually 8 months. Primary host species are grown alongside the seedlings in each pot. S. album has been propagated vegetatively by tissue culture, branch cuttings and cleft grafting. Direct sowing in the fields is used in some situations. Secondary host species should be well established on the planting site before planting. Acacia, Casuarina, Paraserianthes and Sesbania spp are amongst a wide range of successful hosts. Weed control and protection from grazing and fire are essential.
Fruits are edible.
Trees are sometimes lopped for fodder; the foliage of S. album is palatable to grazing animals such as rabbits, sheep, goats, cattle, pigs, horses and camels.
The wood has been used as a fuel but is generally considered too valuable for this purpose.
Timber: S. album is mainly grown for its timber, which weighs 870 kg/cubic m, is durable and strong. Its close grained heartwood is used for ornamental and carving work.
Shade or shelter: Branches grow densely and are capable of intercepting high wind velocity, thus protecting crops.
Tannin or dyestuff: The bark contains about 12-14% tannin and has good potential in the tanning industry. Seeds yield an oil that can be used in the manufacture of paint.
Ornamental: Sandal tree is planted in house gardens as an ornamental.
Trees can be planted along hedges and field boundaries.
Soil improver: Leaves make good green manure.
Intercropping: S. album can be profitably raised along with other trees near or on the farm, thereby providing farmers with additional income.
Essential oil: A valuable oil, ‘the sandal oil’, is distilled from the heartwood (yield varies from 4-10%) and is used in perfumery, soap making and medicines. The roots contain maximum quantity of oil and hence are more valuable.