Botanical Name: Dipterocarpus gracilis
Species: D. gracilis
*Dipterocarpus angustialatus Heim
*Dipterocarpus schmidtii Heim
*Dipterocarpus skinneri King
*Dipterocarpus velutina Vidal
*Dipterocarpus vernicifluus Blanco
Beng : Dholi garjan, Harra garjan, Mashk-haliya garjan
Hin : Gurjan
Kannada : Enne mara, Garjan enne mara
Other : Gurjan
Tibetan : A swa ka rna
Dipterocarpus gracilis is native to E. Asia – Bangladesh, Myanmar, Thailand, Malaysia, Indonesia, Philippines.It is a canopy tree of undisturbed mixed dipterocarp forests at elevations up to 1200 metres. Found in various habitats on alluvial sites; dry hillsides and ridges; limestone. In secondary forests usually present as a pre-disturbance remnant tree.
Dipterocarpus gracilis is an evergreen tree, growing up to 50 metres tall with buttress roots.
The straight, cylindrical bole has small to large, rounded buttresses; it can be free of branches for up to 30 metres and 100 – 180cm in diameter.
The bark is pale grey to mid grey brown, smooth with lenticels when young and become rough and scaly as it mature. The leaves are elliptic to oblong shaped (8 – 18 cm long and 4 – 10 cm wide) with a shortly acuminate leaf tip and an obtuse leaf base. Each leaf has 12—20 pairs of secondary veins. Young leaves are densely covered with golden brown hairs. As the leaf matures, only the mid vein on the upper surface, leaf margin and petiole are covered in golden hairs. Stipule is narrowly lanceolate and densely covered in golden brown hairs.
Flower is about 3.5 – 4 cm long, cream coloured with pink stripe at the centre of each petal, it occurs at the end of the twigs. Flower comprises of 30 stamens, flask – shaped ovary and linear anthers which are tipped by slender tapering appendage that is about two times as long as the anther.
Fruit has 2 large winged-like calyx lobes (10 – 14 cm long and 1.5 – 2.5 cm wide) and 3 shorter wings (1.5 – 2 cm long and 1 cm wide). Nut is globose (2 cm diameter), not ridged and smooth.
The tree is harvested from the wild for its resin, whilst it is also exploited commercially as a source of keruing timber.
Because of habitat loss, and heavy exploitation for timber, the tree is classified as ‘Critically Endangered’ in the IUCN Red List of Threatened Species.
Dipterocarpus gracilis is a tree of low to moderate elevations in the moist tropics, where it can be found at elevations up to 1,200 metres. It grows best in areas where annual daytime temperatures are within the range 24 – 32°c, but can tolerate 10 – 40°c. It can be killed at temperatures of 5°c or lower. It prefers a mean annual rainfall in the range 1,500 – 3,000mm, but tolerates 500 – 4,500mm.
Young trees are shade tolerant, but become increasingly light demanding as they grow larger. Prefers a medium to heavy soil. Prefers a pH in the range 5 – 6, tolerating 4.5 – 6.5.
Members of this genus generally only regenerate naturally in the shade of the forest. Seedlings and saplings can persist in dense forest shade for many years. In their first 2 years the young plants cannot tolerate major openings in the canopy, but after they are well established (about 120cm tall) the canopy can be opened up around them to speed up their growth.
Propagation : Through Seeds.
Edible Uses: Not known to us.
Medicinal Uses: The oleo-resin and also the bark of the tree have medicinal properties.
A balsam resin is obtained from the trunk. It is used in paint oils; as a coat for waterproofing paper; as a varnish for boats, walls and furniture. The resin is obtained by cutting a hole in the trunk near the base (about 90 – 150cm from the ground) and then dipping out the resin with a spoon as it collects there. To prolong the flow, a fire made from dead leaves or brushwood is made in the hole at intervals – this burns off the dried resinous film and allows the resin to flow again.
Dammar is a hard resin, obtained from various trees of Southeast Asia. Traditionally, it is used for purposes such as caulking boats and baskets, as an adhesive, a medicine, as a fuel for torches and sometimes in foods. Dammar has many commercial applications, though many of these uses are less important nowadays due to the advent of synthetic materials. Commercially, it is an ingredient of inks, lacquers, oil paints, varnishes etc, and is used as a glazing agent in foods.
Harvesting of the resin commences when the bole is around 25cm in diameter (approx 20 years old). Triangular cuts (becoming circular with age) are arranged in vertical rows around the trunk. The cuts are several centimetres wide at first, but become enlarged at every tapping and eventually become holes of 15 – 20cm in depth and width. The average number of holes for a tree about 30 metres tall and 60 – 80cm in diameter is 9 – 11 in each of 4 – 5 vertical rows. For the higher holes, the tapper climbs the tree supported by a rattan belt and using the lower holes as footholds.
The exuded resin is allowed to dry on the tree before it is collected. The frequency with which the tree is visited to refreshen the cut varies from once a week to once a month, depending on how far the tree is from the village. Tapping can continue for 30 years.
The light-red wood is heavy, moderately hard and close-grained, but not very durable in contact with the ground. It saws well, but is not used for boxes because of the resin it contains. It is used for house construction. Because of its resinous nature it is less suitable for flooring and woodwork exposed to the sun. It is one of the important sources of keruing timber in Indo-China and is often used as a commercial grade plywood.
The wood can be used to make charcoal.
The tree is a source of keruing timber. We do not have any more specific information for this plant, but a general description of the wood is as follows:-
The heartwood varies from light to dark red-brown or brown to dark brown, sometimes with a purple tint; it is usually well defined from the 5 – 7cm wide band of gray or buff sapwood. The texture is moderately coarse; grain straight or shallowly interlocked; lustre low; there is a strong resinous odour when freshly cut, it is without taste. The wood is moderately heavy to heavy; moderately hard; somewhat durable, being resistant to dry wood borers, fairly resistant to fungi but susceptible to termites, though silica content may be high, resistance to marine borers is erratic. It seasons slowly, with a high risk of checking and distortion; once dry it is poorly stable to moderately stable in service. Silica content is variable, generally less than 0.5%. The wood generally saws and machines well, particularly when green; blunting of cutters can be moderate to severe due to silica content, stellite-tipped and tungsten carbide tools are recommended; it is sometimes difficult to glue; resin adhering to machinery and tools may be troublesome and can also interfere with finishes; nailing and screwing are good, but require pre-boring; gluing is correct, but care is required because of the resin. The wood is used for general construction work, carpentry, panelling, joinery, framework for boats, flooring, pallets, chemical processing equipment, veneer and plywood, suggested for railroad crossties if treated.
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