394 PRACTICAL BOTANY 



A stick of hickory 1x1 inch is pulled apart lengthwise by 

 a load of 32,000 pounds, and crushed by a weight of 8500 

 pounds. The corresponding values for long-leaf pine are 

 17,300 pounds and 7400 pounds. 



364. Advantages of wood over other structural materials. 1 

 Certain disadvantages of wood for construction purposes, such 

 as its combustibility, and liability to decay, are readily evident. 

 Some of its advantages are as follows : 



(1) Wood is far cheaper than metals ; bulk for bulk, it does 

 not on the average cost more than one thirtieth the price of 

 iron or steel. 



(2) Wood is much more easily worked than metals. 



(3) Weight for weight, some wood is stronger than iron 

 or steel. A bar of hickory will stand a stronger pull length- 

 wise than one of wrought iron of equal length and weight. A 

 block of the best hickory or long-leaf pine will bear without 

 crushing a greater load than a block of wrought iron of the 

 same height and weight. 



(4) Wood is light, and therefore much more convenient 

 than metals for many purposes of construction, from build- 

 ing vehicles to making packing cases, and for tool handles 

 and so on. 



(5) Wood is a poor conductor of heat, and on this account 

 is valuable in the construction of houses, railway cars, refrig- 

 erators, and other things. Even in buildings or sailing craft 

 composed largely of steel it is therefore found highly desirable 

 to make the floors, decks, and much of the interior construc- 

 tion of wood. 



(6) Wood is a poor conductor of electricity. This makes 

 it far easier to manage electric wiring in houses or other build- 

 ings in which the floor joists and most of the interior finish 

 consists of wood, than in metal structures. 



(7) Wood usually, when properly finished, has a highly 

 ornamental surface. This makes it possible to give a decorative 



i See Roth, A First Book of Forestry, pp. 232-238. Ginn and Company, 

 Boston. 



