TIMBER VALUES l6l 



30 inches. There must be at least that much to offset the rapid 

 evaporation and for the growing of crops without irrigation 

 60 inches well distributed throughout the year is a safe minimum. 

 Consequently there are some parts of the Philippines where 

 irrigation is the sine qua non of successful agriculture. Slope is 

 the limiting factor second in importance. With the heavy 

 downpours of rain and the open winters slopes cannot be tilled 

 as long as in the temperate zones. As a consequence only the 

 level lands are kept in permanent tillage and clearings made on 

 slopes are only cultivated a few years before being allowed to 

 revert to tree growth. The character of the soil is of importance 

 primarily from the standpoint of its ability to hold water. The 

 open gravels and sands are only tillable where the rainfall is over 

 60 inches per annum. The percentage of rocks in the upper layer 

 is of less importance in the tropics than in temperate regions 

 because the processes of disintegration are rapid and surface rocks 

 quickly break down. Summing up, then, only the level clays and 

 loams are desirable for tillage and the rainfall must be abundant 

 or irrigation possible. Such lands near the market and extensive 

 enough to make up large units are worth fully $100 an acre 

 when ready for cultivation. The extent of the tillable area is a 

 matter of prime importance because tropical agriculture is neces- 

 sarily a large scale enterprise because of the remoteness of 

 markets. Aside from the trifling local demand which is mainly 

 met by produce from their own gardens all foodstuffs must be 

 shipped to the temperate regions for the feeding of the dense 

 populations there. This means that transportation is the con- 

 trolling factor. Consequently there are no large plantations 

 which do not have their own wharfs or ready access to ones 

 where sea-going vessels may dock. Furthermore, a plantation 

 must have its own fleet of vessels or be at the mercy of the 

 transportation companies. In other words the tropics are no 

 place for the small scale agriculturist. Only large concerns 

 farming vast areas and shipping in their own bottoms have been 

 successful. 



Grazing is, as always, a low use of land and this dictum applies 

 with special force to the tropics because there are no high class 



