Speaking

Speak about:

1. The difference between timber, wood, lumber.

2. Softwoods and Hardwoods.

3. The choice of timber utilization by man.

Unit 3

Passive Voice

Indefinite Tenses

Grammar:

Timber

Timber is one of the most important materials used in all branches of industry. Most of the houses in which we live are partly built of timber: they all have wooden floors, wooden doors and wooden window frames.

Artificial textiles are manufactured from cellulose, a substance produced from the woody fiber of plants. Several medicines are obtained from different trees whose medicinal nature is widely known to modern chemists.

Timber was widely used for construction purposes and home needs in prehistoric times. We are told by archeologists that things made of wood were used over 3,500 years ago. Timber was referred to as the best structural material by Greeks and Romans who applied it for construction purposes and whose engineering skill is often spoken about in special literature.

A scientific study of the properties and qualities of wood was started only at the beginning of the 18-th century. The first researches were devoted to the study of the strength of timber. As a result, a considerable amount of data was

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collected giving an idea of the properties of different kinds of timber. The researchers paid much attention to studying the conditions of the growth of the tree. The connection between the mechanical properties and the structure of timber was established and proved.

Being available in large quantities this fibrous material was used in the manufacture of pulp more than a century ago. Pulp was used for the production of paper and for making different kinds of artificial fibers. At first spruce was the chief source of pulp manufacture. Nowadays for this purpose pine is used alongside with spruce.

It should be noted that timber grows in importance. Using new methods and technologies branchwood, slabs, off-cuts and sawdust are not rejected nowadays. They are turned into plastics, wood sugar, alcohol, lignin, fuel. Solid residues such as edgings, trimmings, shavings and the like are adaptable as a raw material for further conversion. Various types of fiberboards and particle boards, composite materials and reconstituted wood products are manufactured and widely used. The possibilities of utilization of residues vary broadly from country to country and from region to region, depending on the size, structure, location and diversity.

General understanding

Read the text attentively and answer the questions.

1. Why is timber one the most important raw materials?

2. What are artificial textiles manufactured from?

3. What is cellulose?

4. How are trees used in medicine?

5. Was timber used in prehistoric times?

6. What countries were the first to apply timber for construction purposes?

7. When was a scientific study of wood started?

8. What properties were studied first?

9. What was established and proved as a result of research work?

10. What was wood used for as a fibrous material?

11. Does timber grow in importance?

12. What products and materials are manufactured from wood nowadays?