Tuesday, 13 March 2012

A kato alu

This basket from Tonga is No. 86 in the Catalogue of Curiosities, where it is described as 'a strong wicker basket.'

Basket, Tonga - 1886.1.1328

It has been identified by Adrienne Kaeppler, currently the Curator of Oceanic Ethnology at the National Museum of Man, Smithsonian Institution, as a kato alu. These baskets were woven from the aerial roots of a type of climbing vine, the alu, Epipremnum pinnatum, which in it's yellow variegated form (Epipremnum pinnatum 'Aureum' - the golden pothos) is a fairly common houseplant here in the UK.

Alu aerial root surrounding palm leaf midribs

This type of basket is still made on Tonga, although alu is becoming scarce, and is difficult to work.  According to Hettinger and Cox, the aerial roots must be harvested between May and October. Before May, the roots are too small, and after October they have reached the ground. The roots are baked in a pit oven for several hours, until soft, and then soaked in seawater until the outer bark can easily be peeled away. The roots can either be used immediately, or dried in the sun to store them.  Before weaving, the roots are split horizontally twice, and the inner sections discarded. The material is soaked in fresh water for up to two days to make it flexible before use. 

Modern baskets are painted black using soot from burnt tuitui (candlenuts, Aleurites moluccana) mixed with the liquid obtained from the inner bark of the koka tree (Bischofia javanica). On examination of the Pitt Rivers basket, it is likely that the alu was dyed before it was woven. Black dyes in the pacific are often obtained using iron rich mud, and it was interesting that on testing the alu with the handheld XRF (X-ray fluorescence unit) it was found to be rich in iron. We thought that the alu may have been dyed in mud in a similar way. However, further research showed that when dyeing the alu, a brown clay, umea, was often added to the dye mixture. It is also used in a similar way to make black dyed barkcloth on Fiji, where the umea is said to act as a fixative, allowing the dyes to adhere to the cloth. The umea could be the source of the iron.

A damaged part of the basket, showing the core of palm leaf midrib and the decoration of plaited coconut fibre

The basket is made by encircling the alu around a coil of coconut palm leaf midribs. The decoration on the basket is made from plaited coconut fibre. Interestingly, this basket is also decorated on the base.

The base of the basket

The basket has been damaged at the sides, probably by being flattened and crushed in the past. This can be more clearly seen the the photo taken in 1970. To conserve the basket, the broken palm leaf midribs will be supported and the shape of the basket restored.

The kato alu photographed in 1970

Kato alu were used to hold personal items, such as gourds containing scented coconut oil. They were also used for the presentation of such items at funerals and weddings. 

The Making of the Kato Alu: A Traditional Tongan Basket
Amy Lafranca Hettinger and Paul Alan Cox
Economic Botany , Vol. 51, No. 2 (Apr. - Jun., 1997), pp. 144-148
Published by: Springer on behalf of New York Botanical Garden Press
Baskets in Polynesia, Wendy Arbeit, University of Hawaii Press, 1990