Langsat

Common names

• Duku
• Kokosan
• Langsat
• Langseh
• Langsep
• Lansa
• Lansone
• Lanzon
• Lanzone

Langsat (scientific name Lansium domesticum) is a fruit-bearing tree belonging to the Meliaceae family. This species has its origin in the Malaysian peninsula and is currently cultivated extensively in various regions of Southeast Asia. The langsat tree grows straight, has a short trunk and its branches are slender or spreading. Usually, this tree grows up to a height of anything between 35 feet and 50 feet (10.5 meters and 15 meters). The bark of this tree is reddish-brown or yellowish-brown and furrowed. This tree bears pinnate leaves that are about 9 inches to 20 inches (22.5 cm to 50 cm) in length and have five to seven alternate leaflets, which are elliptic-oblong, obovate and pointed at both ends. The leaflets measure about 2 3/4 inches to 8 inches (7 cm to 20 cm) in length. They are somewhat rubbery, deep green and lustrous on the upper surface. However, the underside of the leaflets is dull with a noticeable midrib. The flowers are small, plump and usually bisexual. Their color may vary from white to light yellow. The flowers are borne in plain or branched racemes that may either appear as single or in hairy clusters on the oldest branches or the trunk of the tree. Initially, the racemes stand erect, but eventually they become pendant. Each raceme measures about 4 inches to 12 inches (10 cm to 30 cm) long. Langsat fruits are borne in clusters, each cluster comprising anything between 2 to 30 fruits. The shape of the fruits may vary from ovoid-oblong to oval to almost spherical and measure about 1 inch to 2 inches (2.5 cm to 5 cm) across. The color of the fruit may also be different ranging from greyish-yellow to pink or light brownish. The rind is leathery, slender or thick and contains milky latex. The fruit contains about five to six sections of white, translucent fragrant and succulent flesh called arils. Their flavour varies from acidic to partially acidic. The seeds of langsat fruits that stick to the flesh to some extent are found in the first three segments (arils) - not necessarily in all the three segments. The seeds have a green hue and are comparatively large measuring 3/4 inch to 1 inch (2 cm to 2.5 cm) in length and 1/2 to 3/4 inch (1.25 cm to 2 cm) in width. The seeds have an extremely bitter flavour and at times even the flesh may acquire some of their bitterness, especially when the seeds are found clinging to the flesh. The langsat is native to the western regions of Malaysia and is widespread both in the wild as well as cultivated extensively across the Archipelago and the Luzon island in the Philippines. Langsat fruits are not only very popular in this part of the world, but people are also using these trees to reforest the hilly regions. In addition to these regions, langsat is also widely grown in Vietnam and the southern regions of Thailand. In India, langsat trees thrive in the Nilgiris and other regions of South India where the climatic conditions are humid. These fruits are available in abundance in the markets adjoining the places where the trees are grown. Before 1930, this species was introduced into Hawaii and now it is cultivated widely in regions with low elevations. Occasionally, a rare langsat tree may be found in other islands in the Pacific region. Except in Surinam, very few people in the American tropics are aware of langsat or its delicious fruit, let alone its therapeutic properties. Even in Surinam, langsat is not grown in large scale commercially. In 1926, the seeds of langsat were despatched from the Lancetilla Experimental Garden located at Tela in Honduras, while the plants arrived from there in the following year. Although the langsat trees have grown reasonably well in Surinam, they generally do not bear fruits. Even if some trees bear fruits occasionally, their number is very small. However, one will find fruit-bearing langsat trees in Trinidad, where the species was introduced in 1938. Some trees may also be found in Mayaguez, Puerto Rico, and they have been bearing good number of fruits for nearly six decades. In 1930, young specimens of langsat were found growing on St. Croix.

Uses

Apart from being consumed fresh and in the form of syrup and candies, langsat fruits and other parts of this tree have various therapeutic uses. For instance, the dried seeds are pulverized and used in the form of a vermifuge and febrifuge. The bark, which is astringent, is used in the form of a poultice on body areas stung by scorpions. In addition, a decoction prepared from the bark is taken internally to treat malaria and dysentery. The leaves of langsat may be combined with its bark to prepare a decoction. The juice extracted from the leaves of this tree is used as an eye drop to cure inflammation. As far as the therapeutic uses of this tree are concerned, the peel of the fruit is dried out and burned to keep mosquitoes away. In addition, the peels are also used internally for treating diarrhea and eliminating intestinal parasites. The seeds are dried and made into a powder for reducing fever. The bark of the langsat tree (Lansium domesticum) is employed for treating malaria and scorpion stings. The peel of langsat fruits contains elevated amounts of oleoresin, which is used for treating intestinal spasms and diarrhea. The seeds are pulverized and taken internally to treat fever. Resin obtained from the bark of this tree is anti-spasmodic and used for treating a number of conditions including swellings, gastrointestinal (GI) colic and flatulence. Crushed langsat seeds are mixed with water and used in the form of an anti-pyretic and vermifuge. A tincture made from the dried out rind is used internally for curing abdominal colic and diarrhea.

Habitat and cultivation

The langsat is especially a tropical plant. Even when cultivated in its country of origin, it is not possible to cultivate this tree in places higher than 2,100 to 2.500 feet (650 meters to 750 meters). The langsat tree requires a humid environ, lots of moisture and it cannot endure prolong dry spells. The tree will grow better if it is provided with some shade, particularly during its initial years of growth. Langsat trees are best when grown on deep, fertile, properly drained, sandy loam or any other types of soils whose pH is somewhat acidic to neutral and contains profuse organic matter. On the other hand, these trees have a propensity to perform poorly when grown on clay that dehydrates and cracks when there is no rain. Moreover, langsat trees cannot adjust to alkaline soils. These trees also cannot endure water logging even for a few days. Langsat trees are mostly propagated from their seeds. The growth of the seedlings is very sluggish during the first year. It is also possible to propagate trees of this species from cuttings taken from green wood, but it needs plenty of patience and care. Sometimes, langsat is also propagated using the air layering method. However, this process is usually done with larger plants wherein large branches are layered. The rate of success of this method is not very high, as most of the layering fail to give rise to new plants. Young langsat trees are planted at intervals of about 8 meters to 10 meters, depending on the region where they are grown. It is essential to give the young trees a lot of care and attention.

Collection and harvesting

In Malaysia, langsat trees usually bear fruits twice every year. The first fruits are borne during the period between June and July, while the second fruiting occurs in December and January. Sometimes, the second fruiting season extends till February. This fruit-bearing tree is also cultivated in India, where the fruits mature from April to September. On the other hand, the fruiting season of the trees is very short in the Philippines. In fact, most fruits disappear from the market within a month of their availability in the Philippines.