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BASIC LEVEL ROOTS
II In thr first year of a young tree's life the shoot has much the same structure as the the shoot of any common plant. Later the woody structure characteristic of trees develops. As the trunk gets older its outer layer-the bark-gets thicker.Bark is a protective tissue against attacks by animals, insects, cold or heat. Each kind of tree has its own type of leaf, some have two patterns -an adult type and a juvenile form. Air finds its way in and out of the leaf through little pores called stomata. >Vocabulary
WOOD Wood is the material that forms the trunks and branches of trees. Timber is wood cut from the trunk which can be used for constructing houses, boats, furniture and so on. The word lumber is used in the United States to signify sawn and worked timber. As there are many thousands of different kinds of trees in the world so there is a great variety of woods , ranging from the very light to woods so heavy that they sink in water. Over the thousands of years man has learnt to choose timbers most suitable for his purpose. For his arrows straight grain was important. He learnt from experience which wood could be fashioned into boats that would last for decades. In some countries only a few kinds of trees grew naturally and the choice of woods was very limited so trade between countries has developed. >Vocabulary
STRUCTURE OF WOOD Examining the cross section of an oak trunk we can see the bark, annual rings, late and early wood zones, the sap and the heartwood, rays and the pith in the middle. The grain is the lines of fibre in wood that gives a pattern. We speak of straight-grained wood when most of the elements lie parallel to each other and to the axis of the trunk. If the fibres lie at an angle to the trunk the wood is cross-grained. Sometimes zones of growth lie at different angles to each other, then we speak of interlocked grain. The slope of the grain has an important influence on strength of the wood and it also influences the apearance of sawn timber. >Vocabulary
CHARACTERISTICS OF WOOD Timber is devided into two classes, hardwoods and softwoods. Hardwoods come from broad-leaved trees which in the temperate climate shed their leaves in winter. They have open cells that carry moisture throughout the tree. Softwoods come from conifers (cone-bearing) trees. They are non-porous wood, that is their cells are not open-ended. The sap passes from cell to cell through fragile party walls. Remember: the term hard does not actually mean the hardness of the wood! >Vocabulary
HARDWOODS and SOFTWOODS Hardwoods: Oaks fall in three groups on the basis of their wood structure such as a/ white oaks that include European pedunculate and sessile oaks; b/ red oaks which are mainly American; c/ evergreen oaks of which the holm oak or ilex is a European example. Beech is used in large quantities because its wood is straight-grained and has a fine and even texture. Ash is an important British hardwood. Its wood is tough and can be easily bent. >Vocabulary
II Softwoods: Douglas fir is one of the most useful timbers for heavy constructional work. Larch is the most durable of softwoods. Its straight grain makes excellent planking for boats. Spruce is extensively used in Scandinavia for making paper pulp. Though it contains resin ducts it is never very resinous. >Vocabulary
PLANTING a CROP Natural Conditions Hungary lies at the meeting point of three large climatic regions of the temperate zone, so our climate is variable. The natural plant cover is rich in species. The flora of the country includes some 2165 phanerogamic, vascular and cryptogamic plants. The country lies in the zone of broad-leaved (deciduous) forests, the area covered with coniferous woods is small. About two thirds of our forests are natural and the rest are secondary forests or plantations. Two main zonal soil types have developed in our country: the chernozem and the forest soils. The Great Plain /Nagy Alföld/ is in the region of chernozem soils, while the subalpine region, the Transdanubian hills and the two central mountains /the Transdanubian and the Northen Mountains/ belong to the belt of two zonal forest soils, the dark and the brown forest soils. >Vocabulary
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