March 21 is declared as the INTERNATIONAL DAY OF FORESTS

Tree species with potential

| February 1, 2015 | 0 Comments

Manoj Kumar Sarcar & Aruna Basu Sarcar

AT first sight one may think it is a drumstick or some other vegetable, looking at the elongated fruits of Rhizophora – a genus of mangrove forest on the sea shore of tropics and subtropics.

In Tamil, it is called as Kandal, available mainly in the Pichavaram mangrove forests. In India, two common species are Rhizophora rnucronata and Rhizophora apkculata. Both species grow six tol2 (15) m. tall along backwater canals and creeks. They are locally abundant in the Andaman and Nicobar Islands, the Sunderbans (West Bengal and Bangladesh) and in Pichavaram (Taniil Nadu coastline). They form impenetrable barriers by the stilt roots extruding from the trunk of the tree and sloping outwards and downwards to the mud bed and protect the land from coastal erosion.

The species look alike but there are differences. One Is the leaf colour Rhizophora apiculata whose leaves are dark green while Rhizophora mucronata has light green leaves and comparatively smaller ovoid fruit. They occur in tropical South-East Asia. Sri Lanka, Africa, Madagascar, the Seychelles, Mauritius, and North Australia. A few robust trees of a hybrid variety, called as R. larnarekil can be seen in Pichavaram.

The timber and logs are used for construction and making tool handles, posts, etc. The bark of Rhizophora is one rich and cheap sources of tannin (25 to 40 per cent) and oft used in the leather industry. The bark is a powerful astringent in treatment of hemorrhage and angina. It is also used as a cure for diabetes.

It is estimated that the mangrove forests in the Sunderbans and the Andaman and Nicobar Islands together can yield annually about 132,000 tonnes of bark and 6.60 lakh tonnes of wood, indicating its potential to replace all the wattle and quebracho extract at present imported.

Rhizophora protects the sea shore from sea swells, high velocity gales and cyclones. It grows on the outer fringe of the coast land and creeks and act as battalion to the sea shore acting as an interface between land and sea and arrest excessive inundation of land by sea water. Rhizophora alongwith other mangrove species with their highly developed and closely knit root systems, work as natural filters and prevent erosion and loss ot soil fertility during heavy rains and flash floods.

The seeds germinate when the fruit is still on the tree. On falling from the tree, the seedlings grow in the shallow water, Both the species give plenty of fruit in two distinct seasons. The fruit of R. apkIulata is in July and October and R. rnucronata in August and January. Within two or three months, the fruits become mature and they are collected to raise nurseries in potybags (15cm x 2 Scm) to facilitate artificial reproduction.

The seedlings are planted along the banks of creeks or canals. Seedlings planted in canals dug out a year before planting give better results than planting in freshly created canals.

Experiments for artificial reproduction of Rhizhopora and other mangrove species are being done by the Tamil Nadu Forest Department and by the M. S. Swaminathan Research Foundation, Chennai, by making furrows and ridges in the mangrove forest areas in the State. The results were found to be encouraging for taking up large scale planting.

Courtesy: THE HINDU (Sunday, January 18, 1998)

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