Can we have the paper and the trees?

Wednesday, June 12, 1991

By Andrew Katelaris

The use of trees from virgin forest in the production of paper is a phenomenon of the latter part of this century only, though paper itself has been an integral part of human civilisation for thousands of years.

Common teaching has it that the Egyptians produced the first crude writing material by pounding soaked papyrus reeds on flat rocks to fashion a coarse form of paper. In fact, for thousands of years before this, the Chinese had been creating a fine and durable paper with fibre pulp derived from the common hemp plant, of the family Cannabanaceae.

Indeed, until the first third of this century, this plant was the dominant source for paper production. Most surviving texts from last century were printed on hemp paper . What occurred to this industry to make it wither from a position of such commercial importance to its current status?

By far the bulk of hemp fibre was produced to supply the needs of wind-propelled navies. In fact, the word canvas is a Dutch derivative of cannabis. With the replacement of sail by steam power, the area under cultivation contracted greatly.

The discovery and exploitation of very large petrochemical deposits in the first decades of this century generated wealth that gave great power to the individuals who controlled these resources. The development of synthetic fibres derived from this source, such as nylon, and its ready application to high-speed, large-output automated production processes made further inroads on the demand for natural fibres.

This was exacerbated by the slow development of machinery specifically capable of processing hemp fibre on a large and economical scale, such as that developed for the cotton industry.

Racism

A further factor was the politicisation of the use of marijuana by some disadvantaged minorities in US society. After thousands of years of productive cultivation by many different cultures, hemp was deemed a threat to humanity requiring the full force of the police and judiciary to eradicate.

It will probably never be fully known by what arguments the people responsible for this prohibition were influenced, but predominant amongst them would have been racial bigotry directed against blacks, Hispanics and Mexicans and the desire to gain greater power for the police and the state — encouraged, no doubt, by those who owned a controlling share in the evolving synthetics industries.

Due to the extremely favourable weight to strength ratio of hemp fibre, it still finds a place in current manufacture. Most readers would be familiar with hemp rope and hemp fibre widely available at hardware stores for plumbing purposes, but may be surprised to learn that cigarette papers bearing the Job brand are produced under about 8000 hectares of cannabis cultivated at Toulouse and Quimperle, in France. It is also not widely known that some of the finest linens in the world are a blend not of flax and cotton but of hemp and cotton.

To understand how hemp can be of benefit to the vast areas of native forest that fall each year to satisfy our need for paper, a few botanical facts are needed.

Cellulose derived from hemp occurs in two physical forms. The outer bark of the stem yields the long strong fibres that have been used since time immemorial for rope and cloth. These have to be separated from the pith, or phloem, of the centre of the plant by a process known as retting. What results from the separation process is referred to as hemp hurds and would generally be considered a waste product.

Experiments

In an attempt to increase the efficiency of the hemp industry, Lester Dewey, a US Department of Agriculture consultant, conducted experiments in 1916 with paper manufacturers to establish the suitability of hurd pulp as a paper substrate. Adapting existing processes, it was found that a paper could be produced that satisfied all the requirements of the printing industry and, in fact, exceeded in strength and folding endurance paper produced from poplar stock.

It's possible to produce as much paper, in a sustainable manner, from one hectare under hemp as would require four hectares of pulped forest.

A further very important fact is the difference in lignin content between wood and hemp pulp. This averages 18-30% in wood but only 3-4% for hurds. Removing this substance requires much of the harsh bleaching and other chemical treatment that makes the current kraft process such an environmental disaster.

Unfortunately, Dewey's work was too late to rescue the ailing hemp industry, which was under pressure from aggressive chemical conglomerates and a perception at that time that natural resources were essentially infinite.

Of course, there are many potential alternate sources of biomass for paper stock. Kenaf, a tropical fibre plant, bagasse, the fibrous waste remaining after sugar milling, or corn stalks could all be adapted to paper manufacture, but each has specific disadvantages.

Australian climate

The large-scale cultivation of hemp can be carried out in an environmentally sensitive fashion. The suitability of the new Australian colonies as a location for hemp cultivation was established as early as 1845, when Dr Francis Campbell, a notable academic of the day, conducted small-scale experiments.

It was determined that the loamy soils of the river flats from the Hunter region to Grafton provided an ideal climate. This land is at present devoted to cattle grazing and, along with large tracts of Australian agricultural land elsewhere, suffers from the infestation of noxious weeds and gross soil erosion. As reported in Scientific seasons of hemp cultivation will largely clear a field of noxious weeds, because of the dense shock of leaves produced, and will aerate and stabilise the soil through its deep tap-root system. In fact, early agricultural practice utilised this fact to prevent soil erosion after forest fires.

Further, land already devoted to pasture can be readily adapted to hemp cultivation without the necessity of disrupting dwindling native habitats.

The leaf, which has no place in the paper-making process, makes an excellent fodder. Marijuana leaf is used to fatten stock in Borneo and other Asian countries with excellent results, whilst the seed, due to its high vegetable protein content, is currently widely used as a bird feed.

Compared with the woodchip industry, which is extremely capital intensive, a hemp paper industry would be much more labour intensive, providing employment prospects on a large scale.

What are the disadvantages? It is not my intention to debate the merits or otherwise of marijuana as a social drug. It is, however, important to realise that whilst the plant grown for fibre and that cultivated as a recreational drug are the same species, the conditions under which fibre plants must be grown render them totally unsuitable for drug use, with almost undetectable levels of THC.

The earth is experiencing a severe crisis induced by thoughtless exploitation of the planet's resources. In this country, the next decade or two will establish whether our nation has the will and intelligence to tackle the future creatively and apply truly sustainable means of production to satisfy our immediate needs and the needs of future generations. The Industries Commission is currently holding an enquiry into various aspects of resource management. There should be a feasibility study of the industrial-scale cultivation of hemp fibre under licence, for the production of finished paper or at least near-finished paper pulp.

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