The Utilization Of Trees

Since earliest times man has put the forest and its products to innumerable uses particularly for food and shelter. Some of these have declined in importance with the increased use of coal, oil, steel and synthetic chemicals but nevertheless it would be difficult to picture life as we know it today without trees. Formerly, when the population was sparse, there was sufficient natural forest to supply all the timber needed. However, as demand outstripped supply it became necessary to plant trees specially for their wood so that today forestry is a flourishing industry even in a small country like Britain. Hardwoods are obtained mainly from broad-leaved trees, e.g. Oak and Beech, but such species grow slowly and today preference is given to quicker growing conifers which yield softwoods. Large ships are no longer built of timber but vast quantities of hardwood are used for furniture-making and turnery. Softwoods too are employed for making furniture but far larger amounts are used in house construction. Thick trunks and boughs provide planks of timber as well as thin continuous sheets of wood skimmed off by special machines. Strong plywood is made by gluing the sheets together so that the grain of one layer is at right angles to that of the next. Other uses for larger pieces of timber include railway sleepers, telegraph poles and pit props.

Smaller diameter branches and twigs are also utilized. The trimmings from felled trees provide pea and bean sticks; hop poles are produced from coppiced Sweet Chestnut. The long flexible twigs of pollarded Willows still find much use in basket-making. The production of great quantities of wood pulp, especially from North American coniferous forests, is the basis of much of the paper-making industry while the charcoal prepared by incomplete combustion of wood in specially designed kilns is still very important. Large amounts of resin Is extracted from conifers, either by tapping the living trees or after felling. The bark of trees is of little economic importance except for tannin which is still used In treating high-quality leather and for cork which is obtained exclusively from the bark of the Cork Oak,

Trees also provide us with foods of various kinds. Sugar is still extracted from the Sugar Maple on a commercial scale In North America. Apart from this trees also produce many edible seeds and fruits. Although those borne on wild species are often small and of little value, selection, cross-breeding and grafting through the years have resulted in the high-yielding cultivated varieties planted in our gardens and orchards today. Among trees which bear edible fruits are Apple, Pear, Plum, Cherry, Medlar, Olive and Mulberry; those which have edible seeds include Stone Pine, Almond, Hazel and Walnut.

So far we have concentrated on their products but the living trees themselves are of great value. On a utilitarian level some species are important for wind breaks, soil stabilization and hedging. Finally we must not forget the importance of ornamental trees. Compared with some countries the number of native species in Britain is relatively small. Fortunately many introduced trees grow well In our climate and soil and greatly enhance the beauty of roads, parks and gardens. Again the efforts of the horticulturist have resulted In the development of many attractive varieties particularly valuable for their shape, stature, variegated foliage or colourful flowers.

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