Dammar designates a group of resins obtained from Indian or East-Asian trees belonging to the families Dipterocarpaceae and Burseraceae and principally those of the genera Shorea, Balanocarpus, or Hopea. The principal dammars of India are sal dammar, white dammar and black dammar.
Local names :
Sal dammar : Shorea robusta (Family: Dipterocarpaceae)
White dammer: Vateria indica (Family: Dipterocarpaceae)
Black dammar: Canarium strictum (Family: Burseraceae)
Distribution: Trees of these families are Medium to very large, widespread and of very great importance as a source of tropical hardwood throughout the Indian and Southeast Asian regions.
Shorea robusta: lt is a large sub-deciduous tree,found extensively in parts of north, east and central India.
Vateria indica: It is a large, elegant, evergreen tree, indigenous to the evergreen forests of the Western Ghats from North Karnataka to Kerala.
Canarium strictum: This is a large deciduous tree found up to an elevation of about 1500 meters in the Western Ghats and in the west coast forests south of Konkan.
Production in India : 80 tons per annum (approx.).
Other producing countries: Indonesia,Thailand, Vietnam, Laos and Cambodia
Method of harvesting/tapping: Most of the resins are produced by tapping trees, however some are collected in fossilized form from the ground.
Sal dammar: In India, tapping involves removing 3-5 narrow strips of bark, 90-120 cm above the ground- In about 12 days, the grooves become filled with the resin, which oozes out a whitish liquid that becomes brown soon on dying. The cavities of the grooves are freshened, after which the exudation continues and the resin is collected as before. The process is repeated several times in a year .
White dammar: Semi-circular incisions are made on the stem of the tree up to the surface of the sapwood. Blazes or cuts are so spaced as to cause least damage to the tree. The resin starts oozing from the incisions in 3-4 days and continues for 60-90 days. The resin is also exuded when the bark is scorched by lighting fires around the base of the tee. This method gives a high yield of resin but damages the timber and may even kill the tree.
Black dammar: Tapping is done by making vertical incisions on the bark in a belt about 1.8m from the bottom and then lighting a fire round the base of the tree. The resin flows out after two years and continues for about 10 years. The flow lasts for about six months every year from November to April. The viscous resin that oozes out hardens into a somewhat translucent mass shining colour that is of a bright collected manually.
Period of harvesting/collection: Sal dammar collection is done several times during the year altogether three lots are obtained first in June-July, the second in October and the third in January. The resin obtained in June- July is the best in terms of quantity and quality. Black dammar is collected mostly during December to April.
Yield: When tapped once a month in the manner described above, a fully productive tree has been stated to yield about 4 to 5 kg of dammar at each tapping, However,there is known to be genotypic (tree-to-tree) variation in yields and some trees may only be tapped every 3 months because of poor yields.
The exuded resin is allowed to dry on the tree before it is collected.collected resins is cleaned by sieving and hand picking to remove foreign matter and packed in sacks for transfer to points of sale,either Nationally or Internationally.
Dammar is sometimes dewaxed for improving the qualities for varnishes made from it. The dewaxed damar is prepared by dissolving damar in a hydrocarbon solvent and precipitating and removing a high-melting, resinous fraction. The remaining soluble fraction is then more compatible with the cellulose component of cellulose lacquers. In India, an oil is distilled from dammar resin which medicinal purposes.
There is an FAO specification for dammar which gives as a number of limits for such things as arsenic, lead and heavy metal content.
সর্বশেষ সংশোধন করা : 3/1/2020
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