43 



THE CULTURE OF THE CENTRAL AMERICAN 



RUBBER TREE, Vll.f 



( Contimied from Bulletin for fanuary. ) 



By O. F. Cook, Botanist in charge of Investigations in Tropical 

 Agriculture, U. S. Department of Agriculture. 



METHOD OF CLEARING LAND FOR RUBBER PLANTING. 



The question of shade is also involved with that of the method 

 of clearing the land. It is an almost universal custom in tropical 

 countries to clear land by burning the dried forest growth which 

 has been cut down. In fact, the primitive agriculture of the 

 natives of tropical regions could scarcely be conducted on any 

 other basis. There is much loss of fertility by the destruction of 

 vegetable matter and humus, but the amount of labour required to 

 thoroughly clear a piece of forest land in the tropics is prohibi- 

 tively great. The fire not only removes the tangled mass of brush, 

 but it performs an even more useful service in killing the stumps 

 and roots which would otherwise reoccupy the land with new 

 growth in a few weeks, and would remain indefinitely to dispute 

 possession with anything which might be planted. To grow a 

 herbaceous crop on unburned land under such conditions would be 

 extremely difficult, but a tree culture is much more feasible, though 

 whether the method of partial clearing is to be generally advised 

 is not so certain. The gain, if any, is more likely to be found in 

 the sustained fertility of the soil than in any saving of labour in 

 clearing and cleaning the land ; for although there may be a saving 

 at first which will permit an enterprise to reach a paying basis 

 sooner, yet there is in prospect a long and expensive struggle with 

 the persistent natural vegetation rooted in the soil. Moreover, it 

 should be recognized that the conditions under which a plantation 

 is set out in a partially cleared forest are of necessity only 

 temporary. Many of the forest trees will not long survive the 

 unwonted exposure to greater dryness and heat and to the attacks 

 of parasites. The thinning of the forest greatly increases the force 

 of the wind against the remaining tall trees, and in falling these 

 will injure the rubber trees and will often require to be cut away not 

 merely at one point, but at several points. Whatever the merits 

 of the case from the standpoint of the stockholder, the plantation 

 manager of the future is very likely to wish that his predecessors 

 had adopted clean culture. The overhead shade which discourages 

 the undergrowth will also discourage the rubber, and the decrease 

 of such shade will increase the competition of the undergrowth 

 with the rubber. The ideal of rubber culture does not require a 

 roof of shade over the rubber trees nor a dense growth of bushes and 

 vines under them. The roof should be of Castilloa foliage, and 

 the ground should be covered by a mulch of dead leaves and 



t Extrac*^ from the U. S. Depaitraent of Agriculture. Bull. No. 49, Bureau of 

 Plant Industry. 



