Dipterocarpus glandulosus

Dipterocarpus glandulosus is a large canopy tree native to the wet and intermediate zones of Sri Lanka, belonging to the family Dipterocarpaceae. It is one of several Dipterocarpus species that make up Sri Lanka's towering rainforest canopies, and it holds a recognised place in the island's catalogue of Ayurvedic medicinal plants.

What is Dipterocarpus glandulosus and where does it grow?

Dipterocarpus glandulosus is an evergreen tree that typically reaches considerable heights in Sri Lanka's lowland and submontane rainforests. Members of the Dipterocarpus genus are often called "dipterocarps" — a name derived from the Greek for "two-winged fruit," describing the distinctive two-winged seeds that these trees produce. The species is found primarily in the wet zone forests of the south-west and central highlands, where annual rainfall is high and the canopy is dense.

Within Sri Lanka, intact rainforest remnants such as those found in the Sinharaja Forest Reserve represent some of the most important remaining habitat for native Dipterocarpus species. These forests are characterised by multi-layered canopies, high biodiversity, and a mix of endemic tree species that have evolved over millions of years in isolation on the island.

What are the Ayurvedic and traditional medicinal uses of Dipterocarpus glandulosus?

Dipterocarpus glandulosus is catalogued among Sri Lanka's Ayurvedic medicinal plants, a tradition that draws on thousands of years of documented practice. In the broader Dipterocarpus genus, the oleo-resin extracted from tapping the trunk — a substance known as "gurjun oil" in trade — has historically been used in various South and South-East Asian traditional medicine systems for skin ailments, rheumatic complaints, and as an antiseptic.

Within Sri Lankan Ayurveda, the bark, resin, and leaf preparations of related Dipterocarpus species have been employed by traditional physicians ("veda mahattayas") as anti-inflammatory and wound-healing agents. It is worth noting that traditional use should not be treated as a substitute for evidence-based medical treatment. Persons interested in Ayurvedic formulations in Sri Lanka should consult qualified practitioners.

Other medicinal plants catalogued alongside this species in Sri Lankan Ayurvedic practice include Acacia chundra and Pongamia pinnata, both of which have long traditions of therapeutic application on the island.

What does Dipterocarpus glandulosus look like?

Like other members of its genus, D. glandulosus produces large, leathery leaves and a straight, tall trunk — characteristics that made dipterocarps historically valued as timber trees across tropical Asia. The fruit is surrounded by two enlarged, wing-like sepals that assist in wind dispersal, a defining feature of the Dipterocarpaceae family. The flowers are typically pale and fragrant, attracting pollinators during the brief synchronised flowering events that dipterocarps are known for.

The bark surface often shows a characteristic fissured or scaly texture, and the tree may produce a resinous exudate, particularly when the bark is damaged. This resin has both ecological functions — deterring herbivores and sealing wounds — and is the basis for many of the tree's traditional uses.

How significant is Dipterocarpus glandulosus for Sri Lanka's ecology?

Sri Lanka's dipterocarp forests are considered among the most ecologically significant in South Asia. The country has a disproportionately high number of endemic tree species relative to its land area, and Dipterocarpus species contribute substantially to the canopy structure that sustains this biodiversity. These tall emergent trees provide nesting sites for birds, roosting habitat for bats, and structural complexity that supports a rich understory community.

Forest loss and fragmentation have placed many native dipterocarp populations under pressure. Sri Lanka has taken steps to protect key forest areas through national park designations and forest reserves, though habitat connectivity between protected areas remains a conservation challenge. Responsible ecotourism in areas such as the Horton Plains National Park contributes to raising awareness of the island's unique forest heritage.

Is Dipterocarpus glandulosus endemic to Sri Lanka?

Dipterocarpus glandulosus is recorded as a species found in Sri Lanka, and several Dipterocarpus species in the country are endemic or near-endemic. The Dipterocarpaceae family as a whole has its greatest diversity in the forests of South-East Asia, with Sri Lanka representing a westward outlier of the family's range. This geographic isolation has contributed to the evolution of distinct species on the island.

The conservation status of individual Dipterocarpus species in Sri Lanka varies; some are assessed as threatened due to the historical clearance of lowland wet-zone forests for agriculture and plantation crops. Retaining existing forest cover is therefore critical to preserving these species for future generations.

How is Dipterocarpus glandulosus documented in Sri Lankan botany?

Sri Lanka has a well-developed tradition of botanical documentation dating back to colonial-era flora surveys. Dipterocarpus glandulosus is recorded in the official catalogue of Ayurvedic medicinal plants maintained by Sri Lanka's Department of Ayurveda, reflecting the plant's recognised role in indigenous medicine. The species carries the catalog reference LK94006584 within Lakpura's plant documentation system.

Botanical research institutions and herbaria in Sri Lanka continue to document and study native plant species, contributing to both scientific knowledge and conservation planning. Ethnobotanical surveys that record the traditional knowledge of rural communities are particularly important for species like D. glandulosus, where oral traditions hold information not yet fully captured in written literature.

Can visitors see Dipterocarpus glandulosus in the wild in Sri Lanka?

Travellers with an interest in Sri Lanka's native flora are most likely to encounter Dipterocarpus species within protected rainforest areas of the wet zone. The Sinharaja World Heritage Rainforest is the most accessible location for observing primary dipterocarp forest, with guided trails that pass beneath the tall canopy trees. Portions of the central highlands and the forests surrounding the Makandawa Rainforest near Kithulgala also support native forest communities.

Visiting these forests with a knowledgeable local guide greatly enhances the experience — trained naturalists can identify individual tree species, explain their ecological relationships, and point out associated wildlife that would otherwise be difficult to spot.