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The world of forestry

They call it Scrimber
Edible pine pollen
Agroforestry trials in Gabon
Briquettes instead of fuelwood

They call it Scrimber

From Australia comes word of a new technology for processing small diameter logs that is being developed as a result of research by the Commonwealth Scientific and Industrial Research Organization (CSIRO). The process, and the product, are called Scrimber.

The process makes strong structural quality timber out of small logs by separating the wood into interconnected strands, then reforming it into beams using a water-resistant adhesive. More than 85 percent of the log is utilized compared with the 40 percent utilization obtained by current milling methods. Scrimber is expected to open new markets for seven- to ten-year-old plantation trees or thinnings from normal forestry operations. Although the main development programme has concentrated on radiate pine, the Scrimber process can be applied to a wide range of species.

Scrimber was invented ten years ago by CSIRO researcher John Coleman, who conceived the idea of "scrimming", which breaks down the structure of the wood only as far as necessary to allow it to be formed into a desired end-product, rather than destroying the natural alignment of wood fibres and realigning them as more conventional processes do.

SCRIMBER PRODUCTION STAGES untreated log (bottom) to finished beam (top)

After the removal of the bark, tree stems are crushed in a series of rollers in the "scrimming mill", producing bundles of interconnected and aligned strands which largely maintain the original orientation of the wood fibre. These are then dried, coated with adhesive, assembled into desired shapes and put through a hot press.

Manufacturing of Scrimber has come after eight years of research and development by CSIRO's division of Chemical and Wood Technology and Repco Research Pty. Ltd., which established a pilot plant near Melbourne. The pilot plant produces 200 mm by 80 mm rectangular Scrimber, but research officials say that eventually it may be possible to produce huge beams 2 m wide by 500 mm thick.

The first production Scrimber mill has been built in Mt Gambier, South Australia, by the South Australian Timber Corporation (SATCO), the production and marketing arm of the Department of Woods and Forests in South Australia. The mill will use radiate pine from the extensive forests around Mt Gambier to produce Scrimber in market quantities.

According to Australian tree crop journalist Geoff Wilson, Scrimber appears ideal for short-term tree growing by farmers as well as by plantation foresters. Wilson also reports that Scrimber itself may be a fairly high cost product, aimed at the "quality" end of the market, rather than at competing with normal sawn timber sales.

Australian Forest Grower

Edible pine pollen

Like their Australian counterparts (see Scrimber, above), Chilean forest researchers are also experimenting with a potential new product from radiate pine. An unusual study on the harvesting and processing of pine pollen for edible purposes has been completed recently in Concepción by the National Forestry Corporation of Chile (CONAF). The project was the outcome of a winning entry submitted in November 1985 to a competition sponsored by the Confederation of Trade and Industry, the aim of which was to suggest new forms of remunerative rural employment.

The idea was suggested by Manuel Pedreros, a chemical researcher who had worked for CONAF in the region. The project started in January 1986 with the financial support of CONAF and in accordance with the ideas put forward by Pedreros. The initial phase of field-work began in April. A search was made for the most suitable instruments and materials for use in harvesting. A variety of options were examined, preference going to those of low cost and simple operation.

This stage continued until the end of June, when the actual flower harvesting and processing was put into operation. It required the employment of a monthly average of 45 persons until October. The task was carried out primarily in coastal and unirrigated inland areas in the province of Concepción, where test plots measuring 400 m² were established for the collection of radiate and cluster (or coastal) pine flowers at different stages of maturity.

The flowers collected were transported in polythene bags to the extraction centre set up at CONAF's National Forestry Training establishment at Escuadrón. There it was found possible to hasten the maturation by submitting the collected material to stable temperatures of between 20 and 22° C, these being limits within which the flower tends to open and release its pollen-grain content. The grains thus obtained were then screened, enabling a final pure product to be obtained.

About 4000 l of pollen were collected in the four-month work period, equivalent in weight to 150 kg. The coastal pine apparently yielded a greater-than-average amount of pollen, this being attributed to its entirely natural growth, unaffected by any kind of human management or intervention. An adult tree was found to yield about 2 l of pollen a season and one hectare of forest land is able to produce up to 2000 l annually.

Each collector may be expected to gather some 20 l of the substance per day in the form of flowers, but processing in order to obtain pure pollen reduces the yield by 90 percent. The 20 l thus yield 2 l of the final product, or about 0.75 kg each working day.

It is believed that this natural pollen extraction process for nutritional purposes has never before been attempted, and previous local collection experiences had invariably been for genetic improvement purposes. Extraction of pollen by bees (apicultural pollen) has apparently been the only method hitherto used in Chile or elsewhere.

According to Manuel Pedreros, pine pollen contains 22 amino-acids essential to life, in addition to 28 amino-acids of a supplementary character. It also contains minerals, essential oils, enzymes, carbohydrates and proteins as well as all the vitamins indispensable to human life, and is furthermore totally homogeneous. It has an agreeable odour and possesses no particular flavour, thereby favouring its use as an enriching additive in any food product without altering the food's primary characteristics.

Studies are now being made of other uses for the product, but it is thought that its market potential will be considerable in Europe and the United States, where apicultural pollen is successfully sold.

The corporation has given its full support to this investigation, considering on the one hand the possibility that it may provide yet another use for the pine and on the other its value in providing fresh sources of employment for unskilled rural manual labour, thereby restraining migration to cities. An additional feature of interest is that the collection of pollen is carried out in winter, when stable opportunities of employment for such workers are less plentiful.

Some private forestry concerns have already shown interest in starting production in the extensive pine plantation areas in the region. One company alone aims to produce 100 tonnes of pure pine pollen annually, thereby providing employment for 600 rural workers.

A RADIATA PINE PLANTATION pollen harvesting does not harm the trees

Follow-up inspections have been carried out by CONAF specialists in the test areas used during the programme in order to detect any damage to trees, but no such consequences have been identified.

Source: Chilean Forestry News, (January-February 1987)

Agroforestry trials in Gabon

An agroforestry research project has recently been started in Gabon by Unesco and France's National Scientific Research Centre, with the aim of cultivating local forest species and incorporating perennial species into the present slash-and-burn farming system. The project started by observing the first stages of growth of these forest species, because the seedling stage is a vital phase in the life of a plant. The site chosen for the trials was the M'Passa Station of the Tropical Ecology Research Institute in Unesco's Man and the Biosphere Programme reserve, situated near the equator, at an altitude of 500 m. The trials involved transplanting into experimental plots plants collected in the tropical forest, sowing in a nursery a large number of seeds also collected in the forest, identifying the conditions necessary for germination of the seeds, and noting the time taken by many forest and fruit tree species to germinate under experimental conditions.

This project served as the subject for Sophie Miquel's doctoral thesis on "Seedlings and the first stages of growth of forest species in Gabon: potential uses in agroforestry" ("Plantules et premiers stades de croissance des espèces forestières du Gabon: potentialités d'utilisation en agro-foresterie").

The author observes that at the end of a year the survival rate of newly planted young trees in the experimental plots was high for the fast-growing species, while there was heavy mortality among the slow-growing ones. She also notes that the time taken to germinate in the experimental station, where the tests were conducted in a uniform environment favourable to growth, differed from that observed in the forest, where the vegetation itself influences the factors contributing to seed germination. Finally, the absence of dormancy and the rapid germination represent two elements which facilitate cultivation and the planning of sowing periods.

Within the project region the traditional agricultural system is shifting, slash-and-burn cultivation; food crops are grown by women, while the few fruit trees growing near houses are tended by men. Those responsible for the project had difficulty in convincing the villagers that it would be useful to introduce trees into the food crop plantations, where once the harvest is over a spontaneous woody vegetation rapidly springs up.

Success was achieved with certain species in which the cultivators were sufficiently interested.

One of the project's main objectives was therefore to interest local communities, and this led to bringing useful forest species nearer to villages, improving the use of nitrifying plants without upsetting the prevailing farming system, and integrating agroforestry systems into traditional farming practices.

F. Banoun

Briquettes instead of fuelwood

Forced to restrict fuelwood cutting, which contributes to rapid desertification, the Sahelian countries are seeking substitute fuels to meet their energy requirements.

The Council of the Entente, grouping together five of these countries (Benin, Burkina Faso, Côte d'Ivoire, Niger and Togo), therefore requested that studies be undertaken on the use of plant residues for energy. One such study deals with the use of agricultural residues in the form of briquettes. The Fuelwood Association of the French Ministry for Foreign Affairs was made responsible for a pilot project on the domestic use of briquettes in Niger.

The project, which ran from September 1984 to July 1985, tested stoves and fuels. The trials showed that an improved portable metal stove was most suited to conditions in the country, and that briquettes of plant material could be made either from groundnut shells produced on the spot, for which there is very little market at the moment, or from millet stalks. Surveys were conducted among a representative sample of families to ascertain fuelwood use and the acceptability of the briquettes used by these families for six months. The results showed that women preferred a mixture of fuelwood and briquettes, that briquettes had the appeal of modernity, but that if they were to become widely used they would have to be as cheap and available as fuelwood.

Briquettes will probably become acceptable, particularly if the price of fuelwood rises because of scarcity and if the briquette equipment used, adapted to local conditions, makes it possible to lower production costs.

IN THE SAHEL crop residues may be a new source of fuel

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