167 



that young trees planted by man in the open are able not only to resist 

 exposure to the sun, but that they actually thrive better than those 

 planted by natural agencies in the forest. This fact should be sufficient 

 for the purposes of practical agriculture, unless there are reasons for 

 believing that more rubber can be produced in the forest. This is 

 sometimes nr^'ued on the ground that Castilloa is a native of dense 

 forests and can not be expected to yield as much rubber under other 

 conditions. If, however, it is true that Castilloa, or at least Castilloa 

 elastica. is not a forest tree in atiy extreme sense of the words other 

 reasons will be needed to justify shade planting. 



THE RUBBER TREE AND THE TRUMPET TREE 



Castilloa is a relative ot the trumpet tree (Cecropia) and has a similar 

 place in the general economy of nature. Cecropia is wiiely distri- 

 buted in the I'ropics, but is not looked upon as a true forest tree. It is 

 what might be sermed a tree weed It shoots up with great rapidity, 

 and is able for a time to keep ahead of the other vegetation which in 

 most tropical countries promptly takes possession of land neglected 

 after cultivation. Cecropia is thus one of many plants which have 

 rec ived iiidi ect advantage from man's agriculfcuial operations, and it 

 is seldom found in great abu dance except where larger growth has 

 been cleared away. In the undisturbed forest it can nor, w thstaad the 

 competition of the long-lived hard-wood trees and is found but spa- 

 ringly, b^ing limited to oper ings made by fallen timber, forest fires, 

 changes of river channels, and other accidents which give it an oppor- 

 tunity for growth The same appears to \ e even more true of Castilloa. 

 Scattering trees are probably to be found at greater or smaller intes- 

 vals throughout the forests of low elevation \ but there seem to be no 

 indications that they exist in numbers except in forests of rather open 

 growth, such as those which produce also the large palms of the genus 

 .Attaha, and which there is reason to believe do not; represent a truly 

 primeval condition or one of complete forestation, though the List clear- 

 ing may have taken place centuri' s ago. 



CASTILLOA NOT A GENUINE FOREST TREE. 



The native population of the Central American reg:on is commonly 

 supposed to have been much m^re nu'nerous previous to the Spanish 

 conquest, and the numerous and widely distributed ruins prove the 

 former existence of i datively civilised communities in localities which 

 even in the time ot Cortez were apparently forgotten and overgrown 

 with foiests us they are to-day But notwithstanding the former civi- 

 lization of these regions, there seems not to have been found anywhere 

 in Central America an indicati> u of permanent agriculture, such as ter- 

 races, walls, or irrigating ditches. The agriculture of ihf ancient In- 

 dians was probably like that ot the modern, in that each head of a 

 family cut down and burned eaci year a new piece of forest to plant 

 his farm or " milpa." "Where the population is lurge and old forest is 

 no longer accessible the second and successive grt wths are cut at inter- 

 vals of a few years until the tropical i ains have washed away all the 

 fertile surface soil and the district becomes, for the time, a desert, and 

 is abandoned by its human inhabitants Such deserted country is 

 covered first by a ccarse grass and then by a scattering growth of pines, 

 which are in turn crowded out by an invasion of tropical forest vegeta- 



