The basal sheath of the leaf called ‘kanku mattai’ in Tamil is a good source of long, stiff fibres. These fibres are actually vascular bundles or groups of sclerenchymatous fibre cells. The size and colour of the fibres vary; Matured leaf sheaths have more of the dark brown or black strong fibres, while the younger leaf sheaths have relatively light coloured fibres.
Fibre is usually obtained from young palms of 5 — 10 years old. The leaves are cut in an orderly manner from the base upwards; cutting 12 leaves per year from a single palm. The sheath is cut carefully without damaging the stem with a sharp knife leaving a small stump of about 0.5 cm on the trunk. About 12 to 16 leaves from the apex downward are left on the palm. If leaves are harvested every year, the sheaths will yield only medium stiff (i.e. about 50% black fibres), but if harvested once in two years more prime stiff fibres (i.e. 80% black fibres).
Palmyrah fibre has certain desirable qualities besides being hard and stiff. They are resistant to both alkali and acids, resistant to water and attack by termites and other insects. It is for these reasons that palmyrah fibre is preferred to other vegetable fibres. They are used primarily for making sanitary industrial, domestic, scrubbing brushes and road sweeping brushes.
The sheath comes as a pair, is separated and each piece is about 25 – 60 cm long, 10 — 120 cm wide and 1.5 — 2.5 cm thick. Dried leaf sheath or those remain on the palm for many years, after the leaves have been cut and removed, are riot used for extracting fibre. In Sri Lanka, the sheaths are soaked in water and beaten to remove the fibre. But in India, leaf sheath (one day old) are beaten with wooden mallets, when fresh, to separate the fibre from the rest of the tissue. This practice saves time and the yield of fibre is also more. The beaten sheath is combed with the teeth of the petiole (‘karukku’ · Tamil). The fibre is then sized according to the length and bundled to about 10 cm diameter. This is known as ‘Kora fibre". One kilogram of processed fibre can be obtained from about 12 leaves (i.e. per palm). This is processed further, usually at the regional fibre processing centres. Here the bundles are loosened, combed on steel spikes, sized/picked and bundled according to length, given one tie, dried after spreading and re-stacked. The kora fibre contains a mixture of dark brown to black strong fibres and light brovim to white soft fibres.
The bundles are then trimmed with a heavy knife on a wooden bed. Bundles of different length are made, 7-inch long (with 2 ties), 7 — 12 inch lengths (3 ties), and more than 12 inches (4 ties). The
bundles are allowed to dry for sometime on cemented floor. The finished fibre bundles are usually baled into 50 kg weight bales with a dimension of 45cm X 45cm X 50 cm. in order to reduce the volume and save on freight charges. The baling machine used in India is operated manually and has a 20-ton pressing capacity.
Fibres are sometimes dyed and the colours used are black, ash, brown or red. Boiling the fibres in iron tanks, containing water mixed with powdered gallnuts, ferrous sulphate, lissopal, common salt, red/black dye and crude oil, dyes the fibres. Boiling is done for nearly five hours and thereafter the fibre is allowed to remain in the tank till next morning. The dyed fibre is then taken out of the tank and allowed to drain in chambers for 3 to 4 days. During this period whitish fungi grow on the fibre. Then the fibre is spread out in the drying yard (cemented open floor) and dried partially. After this the fibre is first roughly bundled and after combing they are bundled neatly into hanks. As the finished hanks will contain some moisture they are spread in drying yard and well dried.
In Sri Lanka palmyrah fibre was extracted manually until 1991. The palmyrah development board of Sri Lanka initiated a project to mechanize some of the processes such as extraction of fibre and extraction of pulp from ripe fruits under the UNDP/DOSL (SRL/88/005) development project. A proto—type fibre extraction fibre machine consists of a rotary steel spiked comber mounted on to a 4 cm diameter shaft rotating at a speed of 450 — 500 rpm on double ball self aligning bearings was developed. The spikes on this machine are 5cm long, spaced at approximately 3 cm on a wooden cylinder of 30cm diameter and 45 cm in length.