Web of Life

The Candlenut Tree (Aleurites moluccana) has been known in Sri Lanka for a long time and although its origins lie in the Malay Archipelago, it has been known in Sri Lanka for at least 500 years. It grows from sea level to about 1000 meters (3000 ft) in the wet and intermediate zones but always in anthropogenic ecosystems, the largest concentrations being found around Kandy and the Uva basin. It is a tall spreading tree attaining about 20 meters (60 ft) in height and densely covered with three to five lobed leaves, pale green with rusty fuzz on the undersides.

As the tree matures the leaves have less lobes and become simple. Before flowering the young apical leaves on every flowering branch attain a silvery white down giving the impression of silvery rosettes covering the tree. The tiny while flowers are borne about twice a year; these are followed by a cluster of greenish fruit, which contain a hard nut with an oily kernel. An average tree produces about 50 -60 kgs. of nuts annually yielding about 35-40% oil.

In Hawaii the tree is known as Kukui and provided a wealth of uses to its culture. The nuts were roasted, an important pre-requisite before being used as food, as raw nuts may contain a toxin, and pounded to make a relish called 'inamona'. The nuts are similarly used in Malaysia as a condiment in the famous 'satay' sauce. The roasted kernels were also used by fishermen who would chew the nut and spit the chewed mass into the fishing area to make the water smooth and clear.

The green Candlenut fruit yields a sap that has been used by Hawaiians for treating cases of thrush in children. Serving the patient a mixture of the cooked flowers and sweet potatoes also treats thrush. The leaves are used as a poultice for the treatment of swellings and infections. In Sri Lanka the leaves are collected and ploughed into rice fields as green manure.

The tree is also used for the extraction of dyes and stains. The green husk is pounded with water to obtain a pale grey dye while the inner bark is pounded with water yields a reddish brown stain that is used on fishnets. The wood being extremely light, served to make the floats for the nets.

The most important use of the tree in all societies was to provide illumination. Many types of lamps and torches have been developed to use the nut for lighting. One common method was to form a candle by stringing dried kernels on a coconut midrib or bamboo splinter. The candle was then stuck into a sand filled bowl and the upper kernel lit. Each kernel burnt for 2-3 minutes. Thus, a 10-12 kernel candle gave illumination for over 30 minutes. Another was to express the oil for lamps with wicks. The tree was an important utility tree in Sri Lanka commonly found in most home gardens where it supplied much of the rural lighting needs. At the turn of the century, kerosene was introduced for 'modern' lighting needs. At the same time timber from Aleurites was recommended as the packing wood to be used for crating and rubber packing chests. This reward for Aleurites timber resulted in the felling of the large population of trees and by 1950 the tree had become feral or uncultivated, found scattered through the landscape. With the decline of the tree, the knowledge of the use of the tree declined too.

Although the use of Aleurites as a utility tree has declined in Sri Lanka, its leaves and loppings are still used as green manure in much of the Uva District. The green material is placed in the rice fields before sowing and ploughed into the ground.

The commercial extraction of Aleurites oil is accomplished by grinding the seeds to a meal and introducing the pre heated meal ((80 degrees C) into a screw type press operated at a pressure of 850 kg/sq cm. The oil usually requires no further refining except the removal of impurities, usually accomplished by filtration. The residue or press cake forms a useful fertilizer.

Aleurites oil is a fast drying oil similar to Linseed oil or Hemp oil. It is suitable for the manufacture of paint, varnish and lacquer. It is also used as an insulator in the electrical industry and in the preparation of synthetic resins as well as in the manufacture of linoleum, felt carpeting, imitation leather, printing inks, caulking etc.

(Part of the plant series by Rainforest Rescue International facilitated by Lake House Investments Ltd. www.rain4est.org)