Dipterocarpus zeylanicus

Dipterocarpus zeylanicus, commonly known as Hora in Sinhala, is a large tropical tree endemic to Sri Lanka and one of the most ecologically significant members of the Dipterocarpaceae family found on the island. Valued for centuries in traditional Ayurvedic medicine, it also plays a critical role in the forest ecosystems of Sri Lanka's lowland wet zone.

What is Dipterocarpus zeylanicus and where does it grow?

Dipterocarpus zeylanicus belongs to a genus of tall, resin-producing trees widely distributed across tropical Asia. The Sri Lankan species is endemic — meaning it grows naturally nowhere else in the world — and is primarily found in the island's lowland rainforests, particularly in the wet zone of the southwestern quarter. Mature specimens reach considerable heights, with broad canopies that form part of the emergent layer in dense forest stands.

The tree favours moist, well-drained soils in areas with high annual rainfall. Key habitats include forested valleys, riverside forest margins, and the interior of primary rainforest patches. The Sinharaja Forest Reserve, a UNESCO World Heritage Site in the Sabaragamuwa and Southern provinces, is one of the last remaining strongholds for intact lowland rainforest in Sri Lanka and supports a range of Dipterocarp species including this one.

What are the Ayurvedic and traditional uses of Dipterocarpus zeylanicus?

The tree produces a heavy, dark resin — sometimes called wood oil or gurjun oil — extracted from the trunk through traditional tapping methods. In Sri Lankan Ayurvedic practice, this oleoresin has been used for centuries as an external application for skin conditions, joint inflammation, and wound healing. It is listed formally among the medicinal plants recognised in the Ayurvedic pharmacopoeia of Sri Lanka.

The bark and resin are the primary parts used medicinally. Preparations may take the form of oils, balms, or infusions, depending on the therapeutic application. Practitioners traditionally apply the resin-based oil to treat chronic skin disorders and as an analgesic for musculoskeletal pain. As with many plants catalogued in Sri Lanka's Ayurvedic tradition — such as Acacia chundra and Pongamia pinnata — the full pharmacological profile of D. zeylanicus is an ongoing area of scientific study.

What does Dipterocarpus zeylanicus look like?

Mature trees are impressive in scale, often growing over 30 metres tall with a straight, cylindrical bole that can reach considerable girth before the first branch. The bark is rough and dark grey-brown, sometimes deeply furrowed in older specimens. Leaves are large, oval to elliptic, and leathery — an adaptation to the humid, high-rainfall environment.

Flowers are relatively small and pale, typical of the family, and the fruit is the most visually distinctive feature: a nut enclosed by two enlarged, wing-like sepals that act as a rotary glider when the fruit falls, helping disperse seeds away from the parent tree. This winged fruit is characteristic of the entire Dipterocarpaceae family and gives botanists a reliable field identification marker.

Is Dipterocarpus zeylanicus endangered?

Like many endemic Sri Lankan tree species, Dipterocarpus zeylanicus faces significant pressure from habitat loss. Historical deforestation, conversion of lowland wet-zone forest to agriculture and rubber and tea plantations, and selective logging have all reduced its natural range considerably over the past two centuries. The species is considered threatened under international and national assessments.

Conservation efforts are concentrated on protecting the remaining primary forest patches within gazetted reserves. Sri Lanka's Forest Department and several academic institutions are involved in ex-situ conservation programmes, including seed banking and nursery propagation. Visitors to protected areas like Sinharaja may encounter this tree along guided forest trails, where guides can help identify it among the dense canopy.

How does Dipterocarpus zeylanicus fit into Sri Lanka's broader plant heritage?

Sri Lanka has one of the highest levels of plant endemism relative to land area in the world. A substantial proportion of the island's endemic flora carries documented uses in Ayurvedic and traditional medicine — a knowledge system that has been continuously practised here for over two millennia. Dipterocarpus zeylanicus sits within this broader tradition alongside hundreds of other native species whose medicinal properties have been catalogued in classical Sinhala texts and are maintained in modern Ayurvedic practice.

The Ayurvedic medical system in Sri Lanka is regulated and taught at university level, and the Ministry of Indigenous Medicine maintains an official list of recognised medicinal plants. D. zeylanicus features in that catalogue, which underscores its legitimacy as a therapeutic resource rather than merely a piece of folk tradition. Researchers continue to investigate bioactive compounds in the resin and bark to validate traditional claims and explore potential pharmaceutical applications.

Can you see Dipterocarpus zeylanicus in the wild in Sri Lanka?

The best opportunities to encounter mature specimens are within protected forest areas in the wet zone. Guided nature walks through Sinharaja or the Makandawa Rainforest near Kithulgala offer a realistic chance of seeing large Dipterocarps in their natural habitat, especially during the fruiting season when the winged seeds are visible on the forest floor.

Botanical gardens, including the Royal Botanic Gardens at Peradeniya, maintain labelled collections of Sri Lankan endemic trees and may include specimens of D. zeylanicus for visitors who prefer a more accessible setting. For those interested in the intersection of traditional medicine and biodiversity, Sri Lanka's Ayurvedic hospitals and herbal gardens — several of which are open to visitors — sometimes grow or display key medicinal plants alongside educational materials about their uses.

What related Ayurvedic plants should I learn about?

Sri Lanka's Ayurvedic pharmacopoeia is extensive. Alongside Dipterocarpus zeylanicus, several other native species are widely studied and used. Pongamia pinnata is valued for its seed oil in skin treatments, while Acacia chundra contributes astringent compounds used in wound healing and oral health preparations. Compound formulations such as Yogaraja Guggulu and Kaishore Guggulu draw on multiple plant sources and remain widely prescribed in contemporary Ayurvedic clinical practice in Sri Lanka.

Understanding these plants in context — their ecology, their traditional roles, and the forest systems that sustain them — is part of what makes Sri Lanka an unusually rich destination for anyone interested in botanical heritage or natural medicine.