A review of dipterocarps - Center for International Forestry Research
A review of dipterocarps - Center for International Forestry Research
A review of dipterocarps - Center for International Forestry Research
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Non-Timber Forest Products from Dipterocarps<br />
Shorea robusta or sal is another important producer<br />
<strong>of</strong> oleoresin in Bangladesh, India and Nepal. It yields an<br />
oleoresin known as sal dammar, ‘ral’ or lal dhuma’. Earlier<br />
tapping methods gave low and erratic yields. The method<br />
recently employed is to cut 3-5 narrow strips <strong>of</strong> bark<br />
90-120 cm above the ground. When the tree is blazed<br />
the oleoresin oozes out as a whitish liquid and on exposure<br />
it hardens quickly and turns brown. The cut is freshened<br />
by scraping <strong>of</strong>f the hardened resin. In about 12 days the<br />
grooves are filled with resin. The grooves are freshened<br />
and resin is collected periodically in July, October and<br />
January. A good mature tree yields about 5 kg <strong>of</strong> resin<br />
annually.<br />
The essential oil, sal resin, on dry distillation yields<br />
an essential oil, known as ‘chua oil’. The yield <strong>of</strong> the oil<br />
varies from 41 to 68% depending upon the source <strong>of</strong> the<br />
oleoresin samples. The oil is light brownish yellow in<br />
colour and has an agreeable incense-like odour, with<br />
specific gravity 0.9420, acid value 4.42, saponification<br />
value 15.72 and saponification value after acetylation<br />
39.49. It consists <strong>of</strong> 96.0% neutral, 3% and 1% phenolic<br />
and acidic fractions, respectively. Chua oil is used as a<br />
fixative in heavy perfumes, <strong>for</strong> flavouring chewing and<br />
smoking tobacco and in medicine as an antiseptic <strong>for</strong><br />
skin diseases and ear troubles. The non-phenolic portion<br />
<strong>of</strong> the oil has a suppressing effect on the central nervous<br />
system, the phenolic portion is less effective.<br />
Vateria indica is also an important source <strong>of</strong><br />
oleoresin in India. The trade names used <strong>for</strong> the oleoresin<br />
are piney resin, white dammar, Indian copal and dhupa.<br />
The trees are tapped either using semi-circular incisions<br />
or a fire is lit at the base <strong>of</strong> the tree so as to scorch the<br />
bark, which then splits and the resin exudes. The resin is<br />
in three <strong>for</strong>ms: i) compact piney resin which is hard, in<br />
lumps <strong>of</strong> varying shapes, bright orange to dull yellow in<br />
colour, with a glossy fracture and resembling amber in<br />
appearance, is called Indian dammar; ii) cellular s<strong>of</strong>t<br />
piney resin which occurs in shining masses, having<br />
balsamic odour, and light green to yellow or white in<br />
colour, is called a piney varnish; and iii) dark coloured<br />
piney resin from old trees. The resin is a complex<br />
mixture <strong>of</strong> several triterpene hydrocarbons, ketones,<br />
alcohols and acids along with small amounts <strong>of</strong><br />
sesquiterprenes. On distillation, the oleoresin gives an<br />
essential oil (76%) with a balsamic odour. The oil<br />
consists <strong>of</strong> phenolic constituents and azulenes, with the<br />
latter predominating. The essential oil has a marked<br />
antibacterial property against gram negative and gram<br />
190<br />
positive microorganisms (Howes 1949, Chopra et al.<br />
1958). The resin readily dissolves in turpentine,<br />
camphorated alcohol and is used in the manufacture <strong>of</strong><br />
varnishes, paints and anatomical preparations. The<br />
liquefied resin mixed with hot drying oil makes a varnish,<br />
superior to copal, <strong>for</strong> carriages and furniture. The resin<br />
is used to make incense, <strong>for</strong> setting gold ornaments,<br />
caulking boats (Trotter 1940) and in rural areas, resin<br />
mixed with coconut oil is used as torches and candles. It<br />
is a good substitute <strong>for</strong> Malayan dammar and, in solution<br />
in chlor<strong>of</strong>orm, <strong>for</strong> amber in photographers’ varnish. The<br />
resin has medicinal value. It is credited with tonic,<br />
carminative and expectorant properties and is used <strong>for</strong><br />
throat troubles, chronic bronchitis, piles, diarrhoea,<br />
rheumatism, tubercular glands, boils etc. Mixed with<br />
gingili (sesame) oil, it is used <strong>for</strong> gonorrhoea and mixed<br />
with pounded fruits, obtained from Piper longum (longpepper),<br />
and butter or ghee it is useful <strong>for</strong> the treatment<br />
<strong>of</strong> syphilis and ulcers. An ointment <strong>of</strong> resin, wax and the<br />
fat <strong>of</strong> Garcinia indica is effective against carbuncles. It<br />
<strong>for</strong>ms a good emollient <strong>for</strong> plasters and ointment bases<br />
(Kirtikar and Basu 1935, Chopra et al. 1958, WOI<br />
1989a).<br />
In Southeast Asia the important oleoresin trees are<br />
Dipterocarpus cornutus, D. crinitus, D. hasseltii, D.<br />
kerrii and D. grandiflorus. The old method <strong>of</strong> tapping<br />
is by notching a hole in the trunk and blazing to stimulate<br />
further oleoresin flow. This is repeated at about weekly<br />
intervals and the yield per tree is 150 to 280 ml per<br />
tapping (Gianno 1986). A less brutal method has been<br />
developed, known as the barkchipped method<br />
accompanied by application <strong>of</strong> chemical stimulants,<br />
which is less destructive and the yield and oleoresin<br />
quality better (Ibrahim et al. 1990). The oleoresin is<br />
processed to separate the essential oil from the resin.<br />
The essential oil, known commercially as gurjan balsam,<br />
is used as a fixative or a base in perfume preparations<br />
and occasionally as an adulterant <strong>of</strong> patchouli and copaiba<br />
balsam oils. Traditionally the oleoresin is used <strong>for</strong><br />
caulking the inside <strong>of</strong> boats, coating wood as a protection<br />
against weather, in torches, and <strong>for</strong> medicinal purposes.<br />
The oil is also used to make varnishes in backyard<br />
industries (Burkill 1935). While the biggest suppliers<br />
<strong>of</strong> gurjan balsam oil are Indonesia, Malaysia and Thailand,<br />
limited quantities are produced in India and the<br />
Philippines. Sumatra is the biggest producer <strong>of</strong> all, and<br />
in 1984 it produced about 20 tonnes <strong>of</strong> the oil (Lawrence<br />
1985). The oil is now becoming scarce with an