Dominion Museum Notes USES OF THE BARK OF TREES

Dominion, Volume 30, Issue 249, 17 July 1937, Page 2 (Supplement)

Dominion Museum Notes USES OF THE BARK OF TREES

Savagery and Civilisation Both Find it a Valued Asset

Except for its merits in the kindling of a Mazing lire on a winter evening, bark is usually regarded by civilised people as the least useful part of a tree. Yet bark is actually a commercial commodity, playing a larger part in everyday life than the majority of people realise. And if it has its place in civilised households, by savage hearths its services are a hundredfold more important. It provides food, clothing, mats and dyes, and is useful in rudimentary medicine and surgery. Polynesian fishermen use bark to poison fish, and their wives beat it into tapa cloth, lied Indian tribes of old were famous for their birch-bark canoes. The ancient Maori roofed his house with totara bark.

Trees may easily be distinguished by the aspect of their bark. Wherever it is possible to look through a vista of the New Zealand bush, and see the trunks of trees rising out of the undergrowth, one of the easiest trees to identify at any distance is the totara. The bark of this tree is marked at intervals by distinct cross lines cut as if an axe had been inserted and withdrawn preparatory to felling the tree; according to some Maoris these cuts remain on the totara as relics of the work of the gods in the far-away beginning of all things. A rimu trunk, too, can be easily distinguished from, say, a matai, since the rimu barkflakes off in circular pieces, leaving round, pinkish blotches on the stem, which show up in contrast to the black smoothness of the matai. Since the timber generally is considered to be of the main Importance in a tree, the value of the bark usually is overlooked, but it plays a very important part in the growth of the tree. The bark occurs in the young seedling as a protective skin on the stem; its cells are thicker walled than those of the stem and are made of waterproof, corky substance. The function of the bark is to protect the inner, timberforming tissue from excessive wet and cold and from abrasive damage. As the stem grows the layer of bark keeps pace with it by a rapid division and increase of its inner layer of cells so that the outer ones are crowded outward and develop into the hard, impervious cork layer on the exterior.. The bark of trees which grow in hot, dry climates acts also as an insulator between the roasting sun’s rays and the tender inner tissue. It is sometimes seen that when a sheltered tree with

thin bark is suddenly exposed to hot sun rays, the bark becomes dried up and scorched; and I lie quality and growth of timber may be affected. However, in spite of its importance to the tree, the bark from most trees is still considered a waste product and is usually cleared away or burnt as rubbish when the tree is cut for timber. Under modern usage no universal purpose has been found for bark as a whole, but as a natural product of the forest bark of all kinds always has been of the utmost value to native peoples. “Give me of your bark, O Birehtree,” in Longfellow’s “Song of Hiawatha,” i.s a vivid reminder of the value of the tree products to the North American Indian tribes. Canoes wer e fashioned by stretching across a cedar framework the bark of a birch tree, a relative of the silver birch, which, with its small, quaking leaves, has been introduced to this Dominion as an ornamental tree; twisted cedar bark formed fishing lines, resin from the pine trees caulked their craft. In Australia, aborigines cut large pieces of bark from eucalyptus trees and these are shaped and sewn to form canoeg for crossing rivers or even for ocean journeys. Dwelling-places constructed of bark were used by many primitive tribes; and in New Zealand the older Maori houses generally were roofed with large slabs of totara bark. Manuka bark also was employed but was very inferior. Maori Surgery Many were the medicinal and surgical uses of bark to the Maoris. They were good surgeons, and broken limbs were bound with splints of dry totara bark, while pots for carrying water were also fashioned from this bark. The medicinal properties of rata bark were utilised by boiling it for some time and applying the decoction to wounds; The New Zealand lacebark trees

have a characteristic and fascinating bark consisting of an outer hard coat enclosing layer after layer of a fine white silky lacework tissue with strong longitudinal fibres. As may be seen in the exhibit of bark products in the Dominion Museum, these'inner layers were utilised for making fine articles such as small bags and belts, and. in the far north, for hats; while the coarser layers were plaited into fishingnet ropes, and medicinally, the bark was employed as a demulcent. In the preparation of dyes, extracts were made from the bark of the two hinau species and of the mako mako or “wineberry,” to obtain black. The barks of the tanekaha and toa-toa, species of phylloeladus, were used to produce a red colour, while tawhero bark was also used for dyeing fibres for weaving. Phylloeladus bark was tried by early settlers for tanning, and has been exploited commercially in later years, although it was soon superseded by the importation of acacia, or “wattle,” bark, from Australia, and, more recently, by chemical reagents. Discovery of Quinine

The bitter element in kowhai bark was extracted and used as a tonic in much the same way as originated the commercial extraction of quinine from the bark of the South American plant, cinchona. The power of quinine extraction in allaying fevers was first recognised by the civilised world about IG4O, when the wife of a Peruvian high official was treated according to native custom. This led to extensive cultivation of the cinchona tree; and nowadays it is grown commercially in most

tropical countries. The value of the bark drug is difficult to over-estimate, and in tropical areas it is a necessity; the extent of its usefulness in improving general health conditions may be judged by the fact that the Indian Government has undertaken that feinall (loses should be available for sale for a nominal sum at every post office in India.

The most common use of bark is in the preparation of cork articles. The commercial product for this is obtained from certain species of oak growing in Mediterranean. regions, the trees of which develop a corky bark several inches thick. This layer can be removed from the stem periodically without injury to the tree, since it replaces itself ; and the large curled sheets of cork are dried, flattened and prepared for use in a factory built within the cork forest. With the great increase in mechanical and.electrical appliances the demand for cork for water immersion purposes and as an insulating medium has become more and mor insistent.

Tree Bark as Food On« reads of castaways chewing bark in their extremity; but it may come as a surprise to learn that a certain commonly-used household spice is actually the bark of a tree! Among the bark products exhibited may be seen samples of cinnamon bark—this. is obtained from cinnamon, a relation to the camphor tree, and a native of Ceylon, whose thousands of acres are kept under plantation for the commercial production of snice. Only youn"shoots are suitable'for bark production, so the trees are kept coppiced to produce a continual growth of these After removal from the cut the bark strips are subjected to fermentation to help remove the hard outer skin and are then dried into the familiar quills,” ground to form cinnamon powder, or are boiled to distil cinnamon oil.