PART I. OF WOOD IN GENERAL. 



CHAPTER I. 



THE ORIGIN, STRUCTURE, AND DEVELOPMENT OF WOOD 

 AND ITS USE TO THE TREE. 



FEW, if any, of the products of nature are of such manifold utility 

 as wood. Though coal has in many lands largely replaced it as 

 fuel, and as a source of tar, though stone, brick, and iron or steel 

 have often been substituted for it as house-building materials, 

 and the metals last mentioned for the construction of ships, new 

 uses are constantly arising for it, such as railway sleepers, 

 pavements, and paper-making, so as to more than make up for 

 the saving effected by these substitutes. In England and the 

 United States, for example, the consumption of wood per head 

 of the population, during the last half century, has more than 

 doubled. 



Most people are aware that for these manifold uses a great 

 number of different woods are employed in the various countries 

 of the world woods that differ in colour, grain, hardness, weight, 

 flexibility, and other properties almost as widely as the trees by 

 which they are produced vary in foliage, flower, or fruit. It is, 

 however, not so generally recognized that the suitability of wood 

 of any kind for some particular purpose depends mainly upon its 

 internal structure. This structure is determined not by man's 



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