Utilization of forest residues

Utilization of forest residues

Research on methods to transform foliage and residues from the timber industry into products such as animal feed, fertilizers, cosmetics and pharmaceuticals.

In some countries, the disposal of forest industry residues, especially foliage and wood residues, can be a problem. These materials, however, are highly susceptible to being used in an ecological and economic way in the production of energy and countless products of high social demand.

Much information has already been published about its use to generate alternative energy, for example in the production of renewable fuels such as ethanol and ethyl tertiary butyl ether. But this article focuses on the transformation of forest residues into high-value products for various other sectors such as the pharmaceutical, chemical and cosmetic industries, as well as the agricultural sector.

Use of forest residues

Wood cellulose products (lignocellulose): energy, biofertilizers, food supplements; Bioactive substances and natural forest products: wax, chlorophyll derivatives, essential oils, vitamin flour; resins and their derivatives: rosin (Greek fish), turpentine; furniture and boards: furniture, particle board.

These products are currently in different stages of development (laboratory, tests, pilot plant and industrial plant), and the strategy is aimed at consolidating the production and commercialization phase of these products in the region.

Different ways of using wood waste:

Use of forest residues in different countries

1-In the UK: The Timber Research and Development Association (TRADA), based in High Wycombe, believes that new kiln designs will allow the full potential of wood waste to be used as fuel. According to an article by Michael Wigan, published in the English newspaper The Guardian, so far.

2-In Great Britain: wood kilns have had less diffusion and have given results inferior to their possibilities, because, frequently, the wood burns when it is still too wet, which gives a high tar content and causes the clogging of pipes and chimneys.

Ovens with drying compartments could help to solve this problem.

Many logging companies are already using boilers fired with waste wood. Blocks are made from compact sawdust and sold in the form of briquettes or fuel balls.

3-In Scandinavia and the Netherlands: the "energy forest" is already a reality: it is a short-rotation forest, sometimes cultivated under artificial conditions with the main objective of using wood for energy production.

Recently important results have been obtained using some kinds of coniferous needles.

4-In Sweden: for example, spruce and pine needles have been shown to contain substances that can be used for animal feed, vitamin preparations, and chemical semi-finished products. Every year Latvia manufactures 200,000 tons of muka, which is a vitamin flour made from pine needles.

The multiplication of the uses of forest materials will lead many countries to say how many hectares will have to be afforested, reforested or subjected to intensive exploitation, to exploit the new possibilities, especially considering that there is already great competition between different ways of exploiting the earth.

5-It is known that the United States, Finland, Australia and other countries: perform experiments that demonstrate the effectiveness of the use of waste from the wood and foliage processing industry in obtaining animal feed from modern chemical technology and biotechnology.

6-In Canada, the firm State Technology, LTD, markets a product under the trademark "Procell" obtained from forest waste, described as a fibrous product, with a pleasant smell, good taste and that increases the appetite, which constitutes a food supplement in the animal diet.

7-In the former USSR: different experiences are reported in obtaining carbohydrate and / or protein supplements from sawdust, chips and bark, using different methods (Utkin, 1984; Ladinskaya, 1987). Trials carried out by different researchers attest to the nutritional value of such supplements. Examples:

When supplying carbohydrate supplement obtained from wood chips to suckling heifers and cows, it was found that its nutritional value is high and is equivalent to 0.5-0.6 food units (Levanova, 1987) A diet was supplemented to Fattening bulls with saccharified wood mass, in doses of 4 kg per head per day and an increase in 32% in weight of the animals was observed with respect to the control group (Strelski, 1989).

8-At the Center for Plant Biomass Studies of the University of Pinar del Río: a food supplement was obtained called saccharified mass of pine sawdust, which is itself cellulignin enriched in easily assimilated sugars. Its use as a supplement in the diet of birds has been proven (Álvarez, 1993). The nutritional qualities of the product were enriched by cultivating basidiomycete fungi on this substrate, which, through fermentation in a solid state, are capable of profitably bioconverting forest and agricultural residues on a large scale, obtaining a protein enrichment of the substrate by mycelial growth. of the fungus.In agriculture there are numerous scientific reports about the use of sawdust and pine bark in the production of compost for organic fertilization and soil improvement in different countries. Compost is the product of the mixture of all plant and animal waste with the aim that they undergo microbial decomposition through fermentation, becoming, in a reasonable time, what is known as mulch or humus (Dangler, 1993; Milbocker, 1991).

9-In Chile: a group of researchers studied the behavior of soil-sawdust-ash mixtures and verified the possibility of using these residues as soil fertility enhancers, since the mixtures produce an increase in the level of nutritive elements (Crez, 1990).

10-In Spain: the use of pine bark is reported, from which phenols have been extracted to obtain adhesives, for agricultural purposes, since due to its physical and chemical properties it prevents the development of undesirable herbs (López, 1993).

11-North American researchers report positive effects of pulverized pine bark for the increase of fungal populations in the soil (Kokalis-Burelle, 1994).

12-In Portugal, a group of researchers demonstrated the effectiveness of pine and eucalyptus bark as substitutes for zeolite as plant ion exchangers for soil fertilization, composted with other compounds (Guedes de Carvalho, 1994).

13-In Cuba: work has also been carried out to demonstrate the effectiveness of these forest residues for agricultural purposes. At the Forest Research Institute, for example, they obtained organic compost from forest residues, microbiological strains and chemical agents (Harewood, 1989). Other alternatives for the use of forest wood residues are related to its use as an energy source, such as obtaining biogas, activated carbon and fuel ethanol.

All these examples of biomass use show the strong connection between agriculture on the one hand and the decentralized production and use of large amounts of waste.

The world community is very concerned about the sustainable use of natural resources by present and future generations, and about the quality of the environment.

Tends to create an environmental ethic; For example, there is more and more talk of using resources without abusing them, of not forcing them, of reusing them, of doing more with less. The term "sustainable development" was spread by the report of the World Commission on Environment and Development.

It defines sustainable development as that which meets the needs of the present without compromising the ability of future generations to cope with theirs (Maini, 1992). For this reason, no branch of science or technology escapes ecological or environmental analysis. According to Lester Brown, the "Environmental Revolution" is forging a universal and profound change in human values, by transforming, first and foremost, our perceptions about the world in which we live.

Tree foliage

The foliage of felled trees represents a source of usable biomass for obtaining essential oils, waxes, plant extracts (derived from chlorophylls and food concentrates) and forages (Yagodin, 1881; Díaz, 1998).

Although the foliage left on the forest floor provides certain benefits such as nutrient recycling and soil protection against erosion, its excessive accumulation in forests can lead to problems such as increased risk of disease and forest fires.

This is especially the case in logging areas, where Vidal (1995) estimates that 35 to 45 percent of the tree foliage usually remains. Conifers, for example, leave behind 2 to 4 tons per hectare annually. Removing some of the foliage after felling reduces the risk of fire and disease.

Biopreparations from the foliage of forest species contain high levels of chlorophylls and carotenoids, which is why they have a wide range of application in different fields such as pharmaceuticals, cosmetics and veterinary medicine.

The usefulness of chlorophyll derivatives is related to their ability to stimulate tissue regeneration processes and their antimicrobial qualities.

Currently, chlorophyll derivatives have a high national and international market value, due to the tendency to use natural products; It seems that it is time to carry out a market study, since there is a universal tendency to establish small pilot plants for the treatment of biomass.

Wastes from wood processing

Wood residues have been defined in various ways according to their uses. FAO (2000) has defined wood residues as follows:

'Roundwood remaining after the production of forest products in the forest processing industry (ie residues from forest processing) and which has not been reduced to chips or particles. This includes sawmill waste, caps, trimmings, trimmings, veneer log heartwood, veneer scraps, sawdust, bark, carpentry and joinery residues, etc.

Wood chips obtained directly (ie in the forest) from roundwood or waste (ie already accounted for as pulp, round and split wood, or wood chips and particles) are excluded. '

The average generation of residues in the production of sawn wood, for conifers, is around 30 percent of the biomass of the log used, which includes sawdust (5 to 8 percent) and bark (10 to 14 percent) (Kalincha, 1978).

The accumulation of waste in sawmills can hinder the development of the production process, so it is necessary that they be evacuated promptly. Some producers sell them or give them away to companies that give them different uses, but in many cases they are sent to landfills or indiscriminately incinerated, which is a waste of organic matter rich in nutrients.

The sawdust accumulated in the forest or in sawmills constitutes a deposit and a focus for the spread of fungi (especially of the genera Fomes, Schyzophylum and Polyporus, among others) that cause the rot of dying or dead trees with a relatively moisture content. tall. Sawdust is also a fire hazard.

The accumulation of sawdust can also have negative environmental effects:

When decomposing, the carbon dioxide contained in organic matter disperses in the atmosphere.

The sun and high temperatures can cause low-temperature pyrolysis in large piles of sawdust, causing them to emit polluting gases. Combustion also raises the ambient temperature, producing a greenhouse effect.

Waste can be an ideal medium for the spread of pests and diseases.

The issue of the use of wood waste is very complex, especially in developing countries, and depends on economic considerations and means of transport.

Types of treatments used in the improvement of wood waste.

Forest residues, specifically, residues from wood processing, which contain between 60-70% polysaccharides, are a potential source of food for animals and, in their natural state, are not digestible by them.

Scientific literature describes the use of up to 25% untreated sawdust, both coniferous and broadleaf, in cattle rations. It is noted that sawdust does not harm the digestive tract of calves, nor does it cause a toxic effect. The introduction of bulky sawdust in concentrated rations reduces some conditions such as abscess in the liver. The quality of the meat does not diminish. However, as some authors point out, this sawdust in its natural state ensures a normal functioning of the rumen, but it is not a source of food substances.

It has long been known that after delignification of the cell walls of lignified plants and changing their structure by different methods, the fermentative decomposition of wood polysaccharides increases. Some "in vitro" experiments have shown that grinding wood to some extent increases its digestibility.

For the transformation of lignocellulosic biomass into substances digestible by animals, it is necessary:

1- Produce changes in the physical structure of lignified plant tissues, destroying or weakening the links between the fibers.

2- Raise the reaction capacity of the polysaccharide complex of the plant material (first of all cellulose) by transforming its highly oriented intermolecular structure and its depolymerization.

3- Transform polysaccharides in order to create an optimal ratio of mono, oligo and polysaccharides in the product.

4- Enrich the material during or after the chemical transformation process

with proteins, amino acids, fat, macro- and microelements and biologically active substances.

This transformation is achieved by the following methods: Physical action on the biomass by mechanical cutting, radiolysis, heat treatment and others; action of chemical catalysts; action of microorganisms or ferments to achieve a biological conversion; by complex scheme where several methods are combined. Each of these methods has advantages and limitations.

Fate of wood waste

During the wood-making process, a quantity of waste of more than 30% is generated. Among these, sawdust: 5-8% and bark: 10-14%.

The accumulation of waste in sawmills can hinder the development of the production process, so it is necessary that they be evacuated promptly. They are usually sent to landfills or burned, but before this happens, they remain in large piles in the vicinity of industries.

The entities that sell these products are concerned with keeping them well stored, indoors, on tarps, but in most cases these residues remain in the open.

The destination given to the different wastes is not the most rational. Some generating entities sell or give them away to companies that give them different uses; on many occasions they are sent to landfills or indiscriminately incinerated. Incineration is a wasteful technique, since organic matter is rich in nutrients and its final destination must be return to the soil to maintain its fertility.

Some uses of the main processed wood residues

Procedures for the transformation of wood into molasses have been known for more than a century, which can be used in cattle feed in the same way as cane molasses. Also, cellulose is known to have a high energy value for ruminants. During World War II it was used in large quantities in the Scandinavian countries. Equine cattle digest cellulose very well and adult pigs also.

It is known that several countries such as the United States, Finland and Australia carry out experiments that demonstrate the effectiveness of the use of residues from the primary processing industry of wood and foliage in obtaining animal feed from modern chemical technology and biotechnology.

In Canada, the firm Stake Technology Ltd, markets a product under the trademark «Procell» obtained from forest waste, described as a fibrous product, with a pleasant smell, good taste and that increases the appetite, which constitutes a nutritional supplement in the animal diet. From hardwood prehydrolysates they produce xylitol, which is a sugar that reduces the incidence of dental cavities, with a sweetening power comparable to sucrose.

Different experiences are reported in the former USSR in obtaining supplements and / or proteins from sawdust, chips and bark using different methods. Tests carried out by different researchers attest to the nutritional value of such supplements. Examples are the following:

When feeding a carbohydrate supplement obtained from wood chips to suckling steers and cows, it was found that its nutritional value is high and is equivalent to 0.5 - 0.6 feed units. A feed for fattening bulls was supplemented with saccharified mass of wood, in doses of 4 kg per head per day and an increase in 32% in weight of the animals with respect to the control group.In the United States, a group of researchers established different doses for which poplar wood The debarking and poplar pulp could be supplied in the diet of sheep and cattle. In Canada they studied the possibility of using poplar to replace part of the ration of dairy and beef cattle, for which shredded chips were subjected to heat treatment.The product obtained was mixed with protein substances and vitamins, it was enriched with corn and urea. When feeding it to animals, very positive results were obtained. At the Karelia Forest Institute, Russia, a procedure was developed for the use of bark residues, the peculiarity of which is the selective use of the main structural components of the bark. The external part is burned and the internal part is subjected to hydrothermal treatment and after culturing the Candida scotti strain, 54.3% of total protein has been reached.whose peculiarity consists in the selective use of the main structural components of the crust. The external part is burned and the internal part is subjected to hydrothermal treatment and after culturing the Candida scotti strain, 54.3% of total protein has been reached.whose peculiarity consists in the selective use of the main structural components of the crust. The external part is burned and the internal part is subjected to hydrothermal treatment and after culturing the Candida scotti strain, 54.3% of total protein has been reached.

Use of wood residues in agriculture.

Forest residues play an important role in the ecology and protection of forest and agricultural ecosystems, maintaining soil fertility. The content of organic matter and the structure of them helps to control erosion, sedimentation and flooding. Organic matter improves the structure of the soil, increases the capacity for cationic exchange and stabilizes the proportion of nitrogen in mineralization.

The mass of the bark, in comparison with sawdust, contains a greater quantity of nutritive elements. In pine bark it is reported: 0.5% of N; 0.04% P2O5 and 0.13% K2O. Can be used without composting. Pine bark fragments of approximately 5 cm are transformed into humus over the course of two years.

In agriculture there are numerous scientific reports about the use of sawdust and bark of forest species in the preparation of compost for organic fertilization and soil improvement in different countries.

Compost is the mixture of all plant and animal waste with the objective of undergoing microbial decomposition through fermentation, becoming in a reasonable time what is known as mulch or humus.

In Chile, a group of researchers studied the behavior of soil-sawdust-ash mixtures and verified the possibility of using these residues as soil fertility enhancers, since the mixtures produce an increase in the level of nutritive elements.

In Spain the use of pine bark (from which phenols have been extracted to obtain adhesives) is reported for agricultural purposes, since due to its physical and chemical properties it prevents the development of undesirable herbs.

North American researchers report positive effects of pulverized pine bark in increasing fungal populations in the soil.

In Portugal, a group of researchers demonstrated the effectiveness of pine and eucalyptus bark as substitutes for zeolite as plant ion exchangers for soil fertilization, composted with other compounds.

The effects of Leucaena leucocephala residues on the fertility of two types of soils in Paraná were studied by Brazilian researchers and it was found that there was a reduction in acidity and exchangeable aluminum, in addition to an increase in the content of calcium, potassium, organic matter and phosphorus.

Products obtained from forest residues

The traditional uses that have been given to waste can be summarized as fuel (Bintley and Gowen, 1994), a cleaning element for industrial floors, in poultry farms as a litter for birds and other farmed animals (Oconnell and Meaney, 1997) and for different artisan or industrial products (Arends and Donkersloot, 1985). Wood residues are mainly used by the chemical-forestry industry and the board industry. The chemical-forestry industry uses chips and sawdust as raw material to produce alcohol, fodder yeast, furfural (a solvent that is also a precursor of furfuryl alcohol, widely used in the metallurgical industry) and, more recently, carbohydrate, mineral food supplements and / or proteins for animals (Jolkin, 1989). In the board industry, waste is used to make particle board,cleated and medium density fiberboard….etc.

Fertilizers obtained through biotreatment of pine sawdust with earthworms

Obtaining fertilizer from the biotransformation of pine sawdust with earthworms. Fertilizer was produced using the earthworm Eisenia foetida for the biotransformation of bovine excreta and sawdust from Pinus spp. in the ratio of 75:25. The vermiabono obtained is a mixture of chemical components produced by the enzymatic digestion of the organic substrate (excreta and sawdust) and the metabolism of microorganisms. It is dark in color (almost black), uniformly grained, light and porous.

Fertility and development of worms, which depend on food sources, were similar in E. foetida when it was fed with vaccine excreta alone and with the combination of these with 25 percent of Pinus caribaea sawdust. The chemical characteristics of the fertilizer obtained with bovine excreta and sawdust in a 75: 25 ratio are similar to those of other organic fertilizers obtained in Cuba: 1.02 percent N; 0.67 percent of P; 0.42 percent K; 40.51 percent of organic matter; 35 percent moisture, pH = 6.90, C / N = 21:47. obtaining a protein enrichment of the substrate by the mycelial growth of the fungus. 2.

In agriculture there are numerous scientific reports about the use of sawdust and pine bark in the production of compost for organic fertilization and soil improvement in different countries. Compost is the product of the mixture of all plant and animal waste with the aim that they undergo microbial decomposition through fermentation, becoming, in a reasonable time, what is known as mulch or humus (Dangler, 1993; Milbocker, 1991).

In Spain, the use of pine bark is reported, from which phenols have been extracted to obtain adhesives, for agricultural purposes, since due to its physical and chemical properties it prevents the development of undesirable herbs (López, 1993). North American researchers report positive effects of pulverized pine bark in increasing fungal populations in the soil (Kokalis-Burelle, 1994).

In our country, work has also been carried out to demonstrate the effectiveness of these forest residues for agricultural purposes. At the Forest Research Institute, for example, they obtained organic compost from forest residues, microbiological strains and chemical agents (Harewood, 1989).

Hydrolyzed lignin has been used in the production of compost as an organic substance and its value as a soil improver is related to the residual sulfur content that it has (Strajov, 1989). Other alternatives for the use of forest wood residues are related to its use as an energy source, such as obtaining biogas, activated carbon and fuel ethanol. All these examples of the use of biomass show the strong connection between agriculture on the one hand and production and use.

Conclusions

The potentially important social, economic and environmental dimensions, as they open up new perspectives for the sustainable use of forest resources. Economically, a methodology to obtain products of high demand for agriculture, such as animal feed and biofertilizer from non-traditional sources, constitutes an important advance. In the environmental aspect, these transformations offer a good outlet for the excessive foliage that accumulates in the forest and the large volumes of sawdust that accumulate in the sawmills as a by-product of the primary processing of wood.

By eliminating foliage and sawdust in a rational way, you contribute to reducing the polluting effects related to the emission of carbon dioxide into the atmosphere, as well as reducing the risks of fire and the proliferation of diseases.

From the social point of view, when producers and the general population make use of these methodologies and obtain the aforementioned products, they will understand that nature can provide man with everything necessary for his subsistence, if he is treated correctly, it which will contribute to raising the formation of values in relation to the rational exploitation of natural resources.

Bibliography

Arends, GJ and Donkersloot, SS 1985. An overview of possible uses of sawdust. Amsterdam, Center for International Cooperation and Appropiate Technology.

Bintley, WR and Gowen, MM 1994. Forest resources and wood-based biomass energy as rural development assets. Science Publishers, Inc. United States.

Díaz, S. 1998. Behavior of the foliage of Pinus caribaea var. caribaea and Pinus tropicalis in the development of a methodology for obtaining coniferous wax, chlorophyll-carotene paste and forage residue at the bank scale. Doctoral thesis, University of Pinar del Río, Cuba.

FAO. 2000. Yearbook of Forest Products 1998. Rome.

Jolkin, YI 1989. Tekhnologia gidroliznikh proizvodstv. Lesnaya Promishlennost. Moscow.

Kalincha, AA 1978. Les-selskomu khozyaistvu. Lesnaya Promishlennost.

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Oconnell, J. and Meaney, W. 1997. Comparison of shredded newspaper and sawdust as bedding for dairy cows: behavioral, clinical and economic parameters. Irish Veterinary Journal, 50 (3): 167-170.

Pavlutskaya, IS 1983. Poluchenie i ispolzovanie khlorofilcoderzhachikh preparatov iz drevesnoi zeleni. Lesnoi Zhurnal, 4: 23-31.

Vidal, A. 1995. Study of the possibilities of exploiting coniferous canopy biomass in the Pinar del Río province. Doctoral thesis thesis, University of Pinar del Río, Cuba.

Yagodin, VI 1881. Osnovi khimii i tekhnologii pereravotki drevesnoi zeleni. Leningrad, Russian Federation, University of Leningrad http://www.mailxmail.com/curso-wasiduos-madereros-transformacion-uso/tipos-tratamientos-empleados-mejoramiento-wasiduos-woodreros

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