INDO-MALAYAN WOODS. 417 



ENEMIES OF WOOU. 



Fungus and bacterial growth. — The alternate exposure to moisture and 

 dryness is the condition most favorable to such growth. This condition 

 is found in all woods in contact with the ground — piling, hridge timbers, 

 corner posts of houses, etc. In timbers in contact with the ground, as 

 corner posts of houses, telegraph and telephone poles, fence posts, this 

 condition is most marked at and just above the surface of the ground; 

 and that is the region where decay most quickly takes place. 



Dry rot is a form of decay to which some woods are particularly subject. 

 It seems to start in from the end of the wood and may Bometimes be 

 prevented by capping the end of the post or beam with good thick paint. 



Teredo. — This is amollusk which bores into many timbers. It thrives 

 in salt or brackish water and destroys piling, boat planking, etc.. by 

 boring into it in search of a home. It is exceedingly destructive to a 

 large number of timbers and is the most serious problem in wharf con- 

 struction. 



Termites or white ants, known as "anay" or "anay-anay" by Filipinos 

 and Malays, are particularly abundant in the eastern tropics. They at- 

 tack a wide range of different kinds of wood and it may be doubted if 

 any wood is entirely immune from their attacks. Many of the hard and 

 heavy woods are very resistant to them; hut it may he doubted if any 

 of these can entirely resist them without the aid of impregnation. It is 

 often claimed for some particularly hard wood that it is absolutely 

 resistant to the termites; but it will usually be found that it is really 

 only a fortunate chance of location which has prevented the attack. 



Beetles. — Numerous small wood-boring beetles cause great destruction 

 among the woods of the tropics. Sapwood is particularly liable to at- 

 tack ; but the heartwood is also liable to attack in many cases. Numerous 

 hardwoods, however, seem to be entirely free from this pest. A number 

 of woods with hard heart and trashy sapwood are regularly cleaned for 

 the market by being felled and left in the forest, sometimes several years, 

 till the beetles and termites have destroyed the sapwood. 



In general, the very heavy and very hard woods are those least liable 

 to insect attack. Tins is, however, not always true: some of the very 

 hard woods are specially liable to the attacks of termites. 



From what lias been written and what seemed to be generally believed 

 by the trade, the following summary of woods according to their use has 

 been made. 



WOODS EXPOSED TO SALT WATER. 



Piling. — The use of a wood for piling is the extreme test of durability, 

 principally because of the teredo, which speedily destroys most woods. 

 It is to be doubted if there is any wood which is entirely immune from 

 its attack. A pile presents considerable surface to the air and water 

 alternately, furnishing a condition especially favorable to decay; and 



