Santalum freycinetianum

Gaudich.

Forest sandalwood, Freycinet sandalwood

Santalaceae Edible: Seeds 204 iNaturalist observations

iNaturalist· cc-by

iNaturalist· cc-by-nc

Summary

Santalum freycinetianum, the forest sandalwood, Freycinet sandalwood, or ʻIliahi, is a species of flowering tree in the European mistletoe family, Santalaceae, that is endemic to the Hawaiian Islands. Its binomial name commemorates Henri Louis Claude de Saulces de Freycinet, a 19th-century French explorer. ʻIliahi inhabits dry, coastal mesic, mixed mesic, and wet forests on Oʻahu, Kauaʻi, Lānaʻi, Maui, and Molokaʻi at elevations of 250–950 m (820–3,120 ft). It grows in areas that receive 500–3,800 mm (20–150 in) of annual rainfall. Like other members of its genus, ʻiliahi is a root hemi-parasite, deriving some of its nutrients from the host plant; common hosts include koa (Acacia koa), koaiʻa (Acacia koaia), and ʻaʻaliʻi (Dodonaea viscosa).

Description

Slow-growing evergreen tree reaching 10 m in height and spread. Hardy to UK zone 10. Flowers pollinated by bees and insects. Prefers light sandy and medium loamy well-drained soils, grows in poor soils with mildly acid, neutral, mildly alkaline, or very acid pH. Adapts to semi-shade or full sun, prefers dry soil, tolerates drought and maritime exposure. Yellow-brown heartwood is hard, heavy, and fine-textured.

Edible Uses

The seeds are tasty, though their scarcity and high value for propagation make using them as food somewhat impractical.

Medicinal Uses

A drink made from finely ground heartwood powder, combined with Piper methysticum, Eugenia reinwardtiana, Bobea species, and Alphitonia ponderosa, followed by a laxative, was traditionally used to treat venereal diseases in both males and females. For severe sores, the powdered wood is combined with wood from Melicope hawaiensis and Bobea species, along with Piper methysticum and the bark of Syzygium malaccense. A shampoo made from a leaf infusion — sometimes with added ashes of Myoporum sandwicense — has been used to treat dandruff and eliminate head lice.

Distribution

It is a tropical plant.

Where It Grows

Hawaii, Pacific, USA,

Cultivation

A plant usually of moderate elevations in the tropics, usually found between 250 and 950 metres, but it can be found down to almost sea level and up to 3,800 metres. It grows naturally in areas where the mean annual rainfall is in the range 500 - 3,800mm and there is a pronounced dry season of 2 - 5 months. Prefers a position with moderate side shade, but little overhead shade; it grows poorly in deeper shade, but can do well in full sun if attached to a suitable host. Tolerant of a range of soil conditions, including infertile and shallow soils, but grows best in a light to medium, well-drained soil. The plant grows in the wild on a range of volcanic soils, but does not become established on poorly drained sites. Prefers a neutral to slightly alkaline soil with a pH 6.1 - 7.4, but can tolerate 4 - 7.4. Established plants are able to survive a long dry season (up to 5 - 6 months) when attached parasitically to suitably droughttolerant host plants. Although the tree has become much less common in its native habitat due to the ravages of introduced grazing animals and rats, the tree does actually have the potential to become invasive, spreading by seeds and root suckers. However, this has not been seen as a problem in the past, mainly due to the high value of the wood and the ease with which they can be shaded out by taller trees. A slow-growing species, showing annual height increases of 30 - 70cm a year when young. Growth is faster in fertile soils but the tree is then at risk of being shaded out or overtopped by taller, faster growing trees on such sites. Under good conditions, plants begin flowering from an early age, typically about 3 - 4 years, but heavy flowering and fruiting may take 7 - 10 years. Trees can flower and produce fruit throughout the year, usually with two peaks. The flowers produce a weak fragrance. Trees produce root suckers, especially if cut down, when a ring of suckers will often appear several metres away from the original stump. A semi-parasitic plant, obtaining some of its nutriment from the roots of other plants. The plant has green leaves containing chlorophyll, and is thus able to photosynthesize - it relies on host plants only for water and soil nutrients, not for sugars, which it can produce itself . In a natural situation, the plant seems to rely on nitrogen fixing trees such as Acacia and Casuarina, though it is known to parasitize many other legumes, shrubs, herbs and grasses. It normally has more than one host at a time. In the field, seedlings should be planted near potential host plants. Seedlings are generally planted within existing vegetation near potentially suitable hosts; the best host may be Acacia koa. Success is generally good, especially in locations where seedlings can be watered occasionally and weed competition is controlled. Periodic trimming of the secondary host may benefit seedlings.

Propagation

Untreated seeds may take from several months to over a year to germinate, so pre-treatment is strongly recommended. Pre-soaking in water for 3–5 days helps, but more effective methods include complete removal of the seedcoat, soaking for 8–12 hours in 0.05–0.1% gibberellic acid, manual scarification followed by soaking in water, or acid scarification. Sow in a sterile medium such as vermiculite, well-drained potting mix, or sterilized sand-soil mixture. The optimal germination temperature for sandalwoods is around 25°C; bottom-heating germination beds to maintain this temperature is an effective technique. Keep seedlings in 30–50% partial shade. At the four-leaf stage, transplant into containers and introduce a primary host plant — suitable options include native Hawaiian species such as Acacia koa, A. koaia, or Dodonaea viscosa, or non-native species such as Leucaena leucocephala. Seedlings reach planting-out size about 8–9 months after transplanting. Seeds can be stored in a dry, cool place or dried to approximately 8% moisture content and refrigerated at around 5°C; sandalwoods stored under refrigeration can remain viable for several years.

Other Uses

A high-quality essential oil from the heartwood is prized today for perfumery, cosmetics, incense sticks, and aromatherapy. Traditionally it was used to scent coconut oil for hair and body, and to perfume cultural items such as tapa cloth. Powdered heartwood and sapwood are formed into incense or joss sticks for eastern religious ceremonies, using sawdust, carving shavings, or post-distillation wood residue. The yellow-brown wood is hard, heavy, and fine-textured. The finest pieces are used for carving religious statues, handicrafts, art, and decorative furniture, with larger basal sections and roots preferred. In Hawaii it has also been used for musical instruments such as the musical bow. The wood burns well but does not yield useful charcoal; small amounts are added to fires for scent and as a mosquito repellent. Due to scarcity and high cash value it is rarely used traditionally today, though historically it served for canoe paddles, carvings, medicine, and insect repellent. Powdered heartwood was also sprinkled over new tapa cloth to perfume and waterproof it.

References (2)

Elevitch, C.R.(ed.), 2006, Traditional Trees of the Pacific Islands: Their Culture, Environment and Use. Permanent Agriculture Resources, Holualoa, Hawaii. p 695
Voy. Uranie 442, t. 45. 1827