103 



In the second class of fibre plants, the fibres belong to what is termed sclerenchyma tissue, and 

 in Dicotyledons they occur just outside the vascular bundles (veins) in a herb, or in the bark outside the 

 wood in a tree. In Monocotyledons, however, the fibres are usually associated with the vascular bundles 

 which are scattered all through the stem or leaf, and do not occur on the outside of the stem only. As a 

 general rule, therefore, in Dicotyledons this class of fibre is more easily obtained in pure form than in 

 Monocotyledons, where it is associated with the wood tissue and soft, weak, easily decomposed phloem 

 tissue of the vascular bundle. The finer fibres of this type are, therefore, obtained from Dicotyledons 

 (flax, hemp, jute), for the most part. Monocotyledons yield coarser, weaker, darker, or more irregular 

 and rougher fibres of less commercial value (coir, raffia). New Zealand flax (Phormium tenax) is one of 

 the few exceptions, but is at a disadvantage owing to its slow growth under cultivation. 



The third class of fibre is derived from the fibres of wood tissue, and, as a general rule, is 

 employed only for making paper pulp, but has been used in various ways in Germany for weaving to make 

 good the deficiency of proper textile fibres. For wood pulp the fibres should be at least 1 to 4 millimetres 

 long, they must be easily separated by mechanical or chemical treatment, and must, therefore, not be too 

 strongly cemented together, and the less lignified the fibres are, and the moro they consist of unaltered 

 cellulose, the better. 



Bearing the above facts in mind, it may be worth while to consider how far the native plants which 

 have been put forward as fibre plants comply with the above conditions and requirements as possible 

 commercial sources of fibre. 



Eucalyptus Barks as Fibre-yielding Barks for Paper -making. — The first statements to this effect 

 appear to have been made some thirty years ago by Baron von Mueller, and apparently were intended 

 as statements of possibility rather than as statements of fact. Since then, owing to the increased use 

 of wood pulp for paper-making, many once promising materials have lost all value for this purpose. The 

 original statements have, however, been repeated again and again more and more dogmatically without 

 further investigation of the actual economic value of such materials. 



In some respects the barks of Eucalypts have precisely those qualities which should not be 

 present in good paper-pulp materials. Thus the presence of insoluble gum, resin, or kino, or of a high 

 percentage of tannin or colouring materials is a serious disqualification for paper-pulp purposes. The 

 pulp must be capable of ready bleaching without treatment so severe as to damage the fibres, lessen their . 

 strength, or cause their walls to swell. Finally, the bark must not contain suberinized tissue mixed up 

 with the fibres, as is the case with the stringy barks. The suberinized tissue is more resistant than the 

 fibres to caustic soda and retting, and can only be removed even partially by expensive mechanical methods. 

 Until it is removed a satisfactory pulp cannot be obtained. 



Statements as to the value of the barks of Eucalypts for paper-making should, therefore, be 

 received with great caution, unless definite evidence is given of the actual manufacture, cost, and quality 

 of the paper supposed to be yielded by them. 



Eucalyptus obliqua. — The bark is stated to be suitable for the manufacture of packing, printing, 

 or even writing paper, as well as for mill and paste boards, and the pulp is stated to bleach readily. As a 

 matter of fact, the fibres are red or brown in colour, are very weak, and cannot be bleached readily by 

 any cheap method without still further weakening them. As the bark contains large amounts of suberinized 

 non-fibrous tissue, it is unsuitable for paper-making. The same applies to Eucalyptus macrorrhyncha, 

 the red stringy bark. 



The barks of E. globulus, E. amygdalina, E. radiata, E. goniocahjx, E. corymbosa, E. longifolia, 

 E. Stuartiana, and E. rostrata, are also stated to be useful in or suitable for paper-making. I have not 

 been able to procure any samples of paper made from these barks, nor can I find any data as to the cost 

 and value of paper prepared from them. They all appear to have oae or more disqualifications as 

 economically valuable sources of paper-making materials, and hence, until precise information in regard 

 to them can be brought forward, including cost of treatment and value of product, they can be dismissed 

 from the list of materials suitable for paper-making. 



In the " Australian Forestry Journal," March, 1921, p. 84, there is a note on 

 :c Rope from Jarrah Bark " (E. marginata Sm.) In Western Australia there are great 

 accumulations of this at the mills, and experiments are going forward with the object of 



