Styrax tonkinensis b..
Styrax tonkinensis Pierre, nyan khao (white resin) - Siamese benzoin (not in Thailand?)
Styrax benzoides Craib., nyan daeng (red resin) - Sumatran benzoin
Other names: Local names: chan hom, chan pa, chan dong. Meo: tsi yong. Thai: kam yan, khwe, sat
saming, sephobo, sadan. Vietnamese: bo de, cay canh kien trang, cay an tuc huong, ko ngan. English:
Benzoin, benzoin tree, gum resin, gum Benjamin. Trade name: styrax.
Remarks: Lao benzoin has gained popularity on a global level as it is documented in French medical
dictionaries as “Benzoin du Laos”.
Use: Benzoin is a sweet fragrance oleoresin extracted from the tree stem, used as incense in rituals or
ceremonial activities. In Asia in the 2nd century AD mummies were preserved in Styrax balsam in
sarcophagus. Abroad it is mainly known for its use in highclass perfumes and balms, as preservatives in food
processing, in tobacco products and pharmaceuticals.
Aromatherapy benefits are soothing, comforting and warming.
In Indonesia benzoin is still used in production of porcelain. It
is also used as medicine for protection or disinfection of
wounds and to get relief from cough, cold or bronchitis. Also
diuretic, antiseptic for urinary passages and a carminative.
Active ingredients: Nyan khao contains 10-20% benzoic
acid, Coniferyl benzoate at 60-70%, soaresinol 6%, along
with minor portions of vanillin and cinnamic acid. Nyan daeng
constitutes of 2-25% cinnamic acid of the total balsamic acid,
with some benzoresinol, benzoidehyle, benzoic acid and
vanillin which gives a scent of vanilla. Benzoin does not
dissolve in water, only in alcohol.
Harvesting: Oleoresins can be tapped from trees aged 6
years and older with DBH 15-17 cm. Harvesting is done by making v-shaped cuts in the stem and collecting
exuded resin after it hardens to a white-yellowish resin, with a long lasting scent. Resin remains on the tree
during the dry season until the onset of the rains. Benzoin can be harvested every three months. Nyan khao
is used mainly for harvesting resin.
Yields, densities: Benzoin trees produce their maximum yields aged 7-10 years with average yield ca. 0.5
kg/tree. Trees of DBH less than 13 cm are unsuitable for tapping. More resin is obtained from trees having
dark brown, thick bark with deep fissures and obvious parenchyma cells. Below 600 m altitude trees do to
produce benzoin, high humidity and lower temperatures are also important factors. In Luang Prabang an 8
year old fallow field is almost a pure stand of benzoin trees with 875 trees/ha.
Access rules: Often integrated in fallow lands. It has been reported that
due to forest land allocation implemented in 1996 shifting cultivation
cycles have become shorter, 4 years, and thereby excluding the
production of benzoin in fallow lands, requiring 6-7 years of growth.
Sustainability: Intense harvesting can
reduce the potential production or destroy
the tree. Also decreasing fallow periods may
inhibit benzoin production.
Conservation status: Prohibited I, Category B.
Processing: Benzoin oleoresin is extracted with hot alcohol. The alcohol is then
removed leaving a concentrated tincture known as a resin absolute. Benzoin
resin absolute is a thick, brownish-yellow oil with a sweet, balsamic odor and a
hint of vanilla.
Quality criteria: Nyan khao has a superiour production. Only under specific
circumstances the tree produces the very valuable benzoin resin.
Marketing: In 1993 Laos produced over 100 tonnes of benzoin, followed by a drop to 40 tonnes annually,
however a new study revealed that figures are up to 120-150 per year. Export is to France, Thailand, Vietnam
and China. Prices paid in provincial towns to the tappers in the producing areas is currently US$1.5-3/kg. The
price for top quality benzoin paid in China in the beginning of 1991 was reportedly US$22/kg. In 1993 the
price for top quality benzoin in Europe was between US$15-20/kg.
Market prospects: In general exports are reduced with the replacement of chemicals for benzoin. Many
households have seized tapping nhan because of low prices, but poor families are still depending on cash
income. However there are sign in the benzoin market which indicate positive price movements.
Propagation: Cultivation of Styrax trees together with hill rice is an age-old practice. In the province of
Oudomxai and in the North of Luang Phrabang the Styrax forests form part of a shifting cultivation cycle with
long fallow. Trees are also grown in diverse home gardens, rich in edible plants. They can be propagated by
seed. In Lao PDR domestication trials of over 3,000 ha in Luang Phrabang and Huaphan have been
successful. After a nyan khao tree dies the surrounding area is cleared and burned to stimulate its
regeneration, with Zanthoxylum rhetsa (mak khen) trees regenerating naturally. The Styrax tree grows fast,
but will die when taller tree species surround it, as it is an intolerant species.
Description: Nyan daeng has a smooth outer bark, deep maroon and thick inner bark. Nyan khao is a
medium sized deciduous tree 15-20 m high, with DBH 22-28 cm. Outer bark is grey, rough with horizontal
crevasses. The inner bark is thin and light maroon. Single, alternate leaves, ovate, entire margin, acute apex
and rounded base, upper blade is pale green, lower whitish pubescence. Leaf 4-9 cm long, width 15-20 cm.
Terminal axillary inflorescence, panicle 15-20 cm long. Sometimes yellow-orange galls, to 4 cm long, 0.5 cm
wide . Flowers white, with sweet scent. Fruit oval, 1-1.2 cm long 5-7 mm wide, splitting into 3 parts. Seeds
capsules, coffee cream coloured, 3-4 mm long, diameter 2-3 mm.
(Nyan khao) (Nyan daeng)
Distribution & Ecology: Nyan trees occur in wild stands throughout SE Asia. In Laos found from north to
south, with larger populations in provinces of Luang Phrabang, Oudomxai, Houaphan and Phongsali. Fast
growing trees grow mainly in open forest, bamboo forests, fallow lands and on mountain slopes/ridges. Often
associated with Castanopsis sp., Lithocarpus sp. Gmelina aborea, Melia azedarach, Artocarpus sp. and
Pterospermum sp. Pollination is by insects and the drupe is dispersed by birds.
References: INTFP01, NTFPCP00, IBP97, MPV93, SNTFP99, ARCBC, ACS02, NTFPPR04, FTCHXK03,
NVPL59, TFM, LAP, PMC, BKF, TPN, IBP98, MPV93, FRONT, BEER, FES04, IQB95, ITC.