Santalum freycinetianum aka Forest Sandalwood

Santalum freycinetianum is a tree from Hawaii. It belongs to the Santalaceae family. People call it Hawaiian sandalwood or Lanai sandalwood. Kew gives Oʻahu as its native range. It grows on slopes, ridges, and old lava flows. Its forest homes range from dry to wet. Heavy cutting in the early nineteenth century left fewer trees. Useful Tropical Plants cites IUCN's 2016 listing as Endangered.

This slow-growing plant keeps its leaves all year. It can be a shrub or a mid-sized tree. In gardens, it reaches about 30–33 feet [9–10 metres]. Its crown can spread almost as wide as it stands tall. Wild plants may reach 82 feet [25 metres]. Most trunks measure about 0.8–1 foot [0.25–0.30 metres] across. Rare trunks reach about 3 feet [0.9 metres] across. The wood is hard, heavy, and yellow-brown. The heartwood gives a prized oil with a sweet scent.

The plant is a root hemi-parasite: it draws from nearby host plants. Its roots take water and nutrients from these hosts. Growth suffers without a suitable host. It prefers some shade at its sides and little cover above. Deep shade slows growth. With a host, it can grow in full sun. It does best in light to medium soils that drain well. It also grows in poor, shallow soils across a broad pH range. PFAF says it withstands drought and coastal exposure. It lists USDA zones 9–12 for growing this plant.

Flowers may first form three to four years after planting. Bees and other insects move pollen between the flowers. The supplied evidence gives no season for bloom. Seeds are safe to eat, but few are available. They have value for growing new plants. Saving them for this takes priority over eating them. Seeds with no treatment can take months to sprout. Some take more than a year. PFAF says soaking and other seed treatments can help.

People use the scented wood and oil in old and modern ways. Uses include perfume, cosmetics, and incense. They also add scent to cloth or body oil. Past remedies mixed powdered wood with other things for sores and other ailments. People used leaf washes for dandruff and head lice. These past uses do not prove safety or benefit. Both plant references report no known hazards. Neither gives specific evidence on pet safety. Useful Tropical Plants also notes that it may become a weed. It does not say how severe that risk is.