48 CENTKAL AMEKICAN EUBBEE TKEE. 



THE CULTURE OF CASTILLA. 



In attempting- to plan a rational culture for Castilla it will be worse 

 than useless to insist upon all or any of the cultural measures which 

 have been found desirable with coffee, cacao, or other tropical crops. 

 Castilla is not cultivated for the leaves like coca, for the flowers like 

 cloves, for the fruits like oranges, nor for the seeds like coffee. The 

 increase of the size of the trunk and of the amount of milk contained 

 in its inner bark are the objects of cultural solicitude. 



SHADE IN THE CULTURE OF CASTILLA. 



SHADE NOT A NECESSITY. 



Much of the preceding discussion of the habits of Castilla and of 

 the climatic conditions suitable to its culture may also serve as prelim- 

 inary to the consideration of the question whether plantations of 

 Castilla require the shade of larger trees or may be exposed to full 

 sunlight. The argument that Castilla always grows in shaded loca- 

 tions in nature is by no means conclusive, since it is well known that 

 many forest trees thrive better when the} 7 have the opportunity of 

 standing alone and are free from the close competition for food and 

 sunlight implied by forest conditions. It is also certain that Castilla 

 is not only able to obtain an existence in the open, but that it makes 

 much more rapid growth quite without shade than it does in the forest. 

 If the problem were merely to secure the quick growth of Castilla, 

 there would be no hesitation between these two methods of planting; 

 but there are man} 7 stages between dense forest and clean culture, and 

 the question may well be raised whether the conditions most favorable 

 for rubber production are not to be found in some of these. Advo- 

 cates of both extremes and all intermediate conditions are not lacking, 

 so that the question of shade with Castilla bids fair to become as com- 

 plicated and as extensively debated as with coffee and cacao. More- 

 over, as with those crops, it may be found to have no general solution, 

 but to depend upon local conditions of soil and climate. 



That rubber can be grown under forest conditions there can be no 

 doubt, since all the natural supplies are to be credited to this method 

 of production, but the desirability of forest planting does not neces- 

 sarily follow, since it is equally certain that under the deep shade the 

 trees grow with an extreme slowness, which would exhaust the patience 

 of any investor. Moreover, as previously shown, it may well be 

 doubted whether a plantation of Castilla would ever grow to normal 

 maturity in the undisturbed forest; the indications are that only those 

 trees survive which are able to profit by accidents to their larger 

 neighbors and thus receive more sunlight than usually reaches the 

 undergrowth of a dense tropical forest. In other words, regular 

 forest planting does not mean the placing of Castilla under conditions 



