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Non-Timber Uses For Trees
Europe's most heavily forested country, with over three quarters of the land area (23 million hectares) under forest cover, Finland is world famous for its timber products. However, trees are a very versatile material that can be used for a wide variety of non-timber applications by exploiting their structural component tissues and the oil and resinous metabolites contained in the timber, roots, bark and leaves.
The most important non-timber use of wood today is the production of pulp to make paper. Pulps are produced either through thermo-mechanical or by chemical action. Other less known uses (except in Finland) include; xylitol, famine bread and birch sap.
Xylitol is a naturally occurring sweetener. It can be found, in berries, fruit, vegetables, mushrooms and birch trees. It is manufactured by chopping up and rendering down the structural fibre of the wood, xylan. Xylitol was first discovered by German and French chemists in the late 19th century. In the Soviet Union it has been used for decades as a sweetener for diabetics and, in Germany, in solutions for intravenous feeding. In China xylitol has been used for various medical purposes. The dental significance of xylitol was ‘discovered’ in Finland in the early 70's, when scientists at Turku University showed it could prevent caries. Xylitol-Jenkki, the first xylitol chewing gum in the world, was launched by the Finnish company Leaf in 1975.
Famine bread or bark bread is made partially or, in the worst times wholly, of the inner bark of the silver birch or pine tree. Famine bread was regularly eaten in large areas of eastern and northern Finland during times of crop failures and food shortages. Lacking in taste and sour to the tongue, it was perceived to be unwholesome and lacking in nutritional value. However, research conducted on behalf of the Finnish defence forces in the 1970s concluded it was both non-toxic and nutritious. Even during the 20th century wars, when food was rationed, famine bread was eaten, thus saving thousands of lives.
In Finland the birch sap season starts in April/May and lasts from three to five weeks. A renewable resource, birch sap is a solution of nutrients produced by the tree for its own use. As the birch tree absorbs water and nutrients from the soil, it also converts substances that it has stored into sugar. There are many different ways to tap a birch tree. Small amounts of sap can be collected by cutting the tops of branches and pushing them inside a bottle. Another method is to drill a slanted hole a few centimetres deep into the trunk about half a metre from the ground and push a tube called a spile into it to tap the liquid.
Sap has been consumed for centuries in the Nordic Countries, as well as in Central Europe, Canada, and Korea. It contains potassium, calcium, magnesium, zinc, vitamin C, amino acids and protein. This has lead to many claimed benefits of drinking birch sap, including: a cure for fatigue, scurvy, rickets, kidney disease, arthritis, gout and multiple sclerosis. There is, however, a lack of medical evidence to support this.
Other non-timber uses for trees include: Resins, waxes and oils which can be extracted from living trees by 'tapping', or from the bark and wood during pulping. Tall oil is used to produce a variety of resins and these products are often referred to as 'Naval Products', which derives from their traditional use in shipbuilding. Turpentine/pine oil which is used as a solvent in paints and varnishes. Gums from larch species, is mainly used as a replacement for gum arabic in food, cosmetic and pharmaceutical products.
Mulches, in recent years there has been an increase in the use of wood chips, wood mulch and bark for recreational purposes such as playgrounds, public gardens, motorway embankments and individual household gardens, as well as for paths and tracks etc. Much of this is derived from thinnings, harvesting residues or sawmill waste. Currently, spruce and pine are the most popular wood for this application. Coarser wood and bark can also be used in paddocks and gallops.
Mike Bangle is the owner of Talking English language consultancy and can be contacted at mike.bangle(at)phnet.fi
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