Dammar and wood oil
H. N. Ridley, Director of the Singapore Botanic Gardens, published this concise taxonomic and economic survey of dammar resins and wood oils (gurjun) in the Journal of the Straits Branch of the Royal Asiatic Society in 1900. Writing at a moment when both commodities were in commercial decline, Ridley maps the botanical sources, local trade nomenclature, and extraction practices of these Dipterocarp-derived products across the Malay Peninsula, arguing that the near-disappearance of wood oil from commerce and the contraction of the dammar trade reflected the exhaustion of accessible forest resources rather than any loss of demand for the products themselves.
Summary
Ridley’s article addresses a practical problem of colonial economic botany: the identification and classification of the many locally named resins and oils that the Malay Peninsula had historically supplied to regional and international markets. The central difficulty he confronts is one of nomenclature. Native and trade names for dammar refer primarily to the form, colour, and transparency of the resin mass rather than to the producing tree, making it extremely hard for a European trader or manufacturer to know what botanical source underlies a given lot. Ridley works through this by correlating local names with species, drawing on his own field collections and on the observations of earlier authorities such as Cooke and Watt.
The article is divided into two main sections. The first treats dammar in its various forms—exuded from wounds, filling hollows, forming plates beneath bark, or dripping as stalactitic and stalagmitic masses—and catalogues the local names against their probable botanical sources in Shorea, Hopea, Anisoptera, and, more loosely, Canarium, Triomma, Santiria, and Calophyllum. A particularly interesting thread is the discussion of Kelulut (stingless Trigona bees), which collect and mix resins from multiple tree species to build their nests, explaining why the “dammar” from these nests is botanically heterogeneous. The second section turns to wood oil (gurjun, minyak keruing) from Dipterocarpus species, describing the extraction method—deep square holes cut into the stem and charred to stimulate flow—and identifying the principal oil-producing species.
Throughout, Ridley’s narrative is shaped by the observation that both commodities were in steep decline. The dammar export trade from Singapore had contracted to cat’s-eye dammar and Celebes copal, while wood oil had “nearly disappeared out of commerce” because the trees are so isolated in the forest that supplying even a small quantity required traversing vast tracts, and because over-extraction had killed many trees.
Key Findings
- The Singapore export trade in dammar had declined to the point where only cat’s-eye dammar (Damar mata kuching, from Hopea species) and Celebes copal (from Shorea selanica) were still shipped, with no remaining demand for the less transparent varieties (p. 89).
- Wood oil extraction involved cutting holes approximately six inches square into the Dipterocarpus stem, charring the interior with fire to stimulate exudation, and collecting the oil in kerosene tins; the process was repeated by re-burning the wound when flow ceased (p. 93).
- The chief oil-producing species identified for the peninsula are D. grandiflorus (Minyak Keruing Dadeh), D. kerrii (Minyak Keruing Chaier), D. hasseltii (Minyak Keruing Sudi), and D. crinitus (Minyak Keruing Bulu); the greater part of commercial wood oils of the period were exported from Rangoon and derived from Burmese Dipterocarpus species distinct from those of the peninsula (pp. 93–94).
- Kelulut (stingless Trigona) bees collect resins from at least five different genera—Shorea, Garcinia, Calophyllum, Triomma, and Pterocarpus indicus—and incorporate them into their nest structure, which is why the “dammar” from these nests is a heterogeneous mixture rather than a single-species product (pp. 92–93).
- Damar Orientalis, a large conifer of the hill ranges in Penang and Perak, produces a very liquid turpentine that Cooke recorded as being sold to varnish makers under the name “East India Dammar” and much esteemed by natives for incense (p. 92).
- The oil from D. hasseltii is described as one of the best, with fruits whose pericarp can contain nothing but clear transparent oil; the oil separates on standing into a liquid fraction (Chaier) and a thick semi-solid resin (Beku) (p. 94).
Conclusion
Ridley’s definitive takeaway is that the economic importance of both dammar and wood oil in the Straits Settlements was a function of forest accessibility rather than of any inherent scarcity of the trees themselves. Because Dipterocarpus and dammar-producing Shorea and Hopea trees occur as isolated individuals spread across vast tracts of primary forest, the labour cost of collection rose sharply as the most accessible specimens were exhausted or killed by over-tapping, and the commodities simply withdrew from the market. The article thus serves as a contemporaneous record of the early stages of tropical forest resource depletion in the Malay Peninsula, framed in the language of economic botany.
Context
- Ridley held the position of Director of the Singapore Botanic Gardens (1887–1913) and was the pre-eminent authority on the flora of the Straits Settlements; this article reflects his standard practice of combining field observation with taxonomic identification to serve the practical needs of colonial trade and industry.
- The article draws on Ridley’s own collections (including specimens from Johore and the Carimon islands) and on earlier published accounts by Cooke (Gums and Resins) and Watt (Dictionary of Economic Plants of India), positioning it within the late-Victorian tradition of economic-botanical surveying that underpinned colonial agricultural policy.