PHILIPPINE FIREWOOD. 19 



SUMMARY. 



1. The chief woods used in the Philippines as fuel are the Bhizopho- 

 racece, although locally anything available is used. The consumption of 

 firewood is at least 200,000 cubic meters annually. 



2. Oven-dried wood will take up somewhat less moisture from the air 

 than air-dried wood will retain of the original moisture of the green 

 stick. 



3. The best seasoned wood in this climate will retain moisture equal to 

 12.5 to 13 per cent of the weight of the dry wood. The dry weight is the 

 only constant basis on which to compute the percentages of moisture 

 and ash. 



4. Some of the tables given are : (a) The determination of the calorific 

 values of some Philippine woods; (&) The determination of the calorific 

 values of some Philippine barks; (c) Analyses of wood ash; (d) The 

 determination of the specific gravities of some Philippine woods; (e) The 

 approximate fuel value of North American and Philippine firewoods. 



5. The available heating value of the combustible matter of wood, 

 wood — (water-|-ash), is practically constant and is equal to 4,418 

 calories. From this number the available heating value of a wood may 

 be calculated when its moisture and ash content are known, as follows : 



/-I 1 • ..,„.,/ 100— (per cent water + per cent ash V „ ^^ , , 



Calories = 4418 X \ tkf. — : / — 6 X per cent water. 



6. The three most important factors controlling the value of a wood 

 for fuel are the content of moisture, the content of ash and the specific 

 gravity. 



7. The volatile constituents of a mangrove ash are large and may 

 condense as clinker on the walls of a furnace or glaze the surface of any- 

 thing with which they come in contact. 



