Gums, Resins, 



iio 



[August, 1908. 



The first requirement is the right kind 

 of soil and climate, and at the same time 

 an honest and competent administration. 

 If these conditions are fulfilled, rubber 

 planting promises to become the most 

 profitable tropical industry. 



The commercial exploitation of various 

 rubber-producing plants was naturally 

 first taken up by the nations which owned 

 tropical colonies or tropical lands. It 

 was in these same countries the profitable- 

 ness and possibility of rubber culture 

 were first realized. There was naturally 

 at first a certain hesitation, but of late 

 years an increasing faith in rubber is 

 evident from the fact that more and 

 more capital is being diverted to this 

 new tropical industry. 



There are few plants that are better 

 adapted to cultivation than the principal 

 rubber-producing trees. It has now been 

 fully demonstrated that rubber can be 

 grown profitably on a commercial scale, 

 and that plantation rubber can be pro- 

 duced cheaper and better than the 

 product of the wild tree. Many mistakes 

 are yet made and comparatively little 

 knowledge exists regarding cultural 

 methods, but with the increased atten- 

 tion now being paid to rubber cultivation 

 it can be hoped that present defects and 

 shortcomings will be corrected in a not 

 too distant future. 



Rubber planters in Mexico and Central 

 America have been experimenting re- 

 garding cultural methods for a good 

 many years, and it is only of late definite 

 results have been forthcoming. In many 

 special questions no ultimate conclusions 

 have yet been arrived at, and we cannot 

 say that we are absolutely certain as to 

 the best methods in any particular stage 

 of the cultivation or preparation of 

 Castilloa rubber. 



In regard to soil requirements Castilloa 

 needs an open porous soil, well drained, 

 but with sufficient underground water 

 supply. The chemical consistency of the 

 soil or its relative richness is ot little 

 importance. Stagnant water or very- 

 acid soil is detrimental, and thin soil 

 with hard impermeable subsoil will grow 

 Castilloa for a few years, but when 

 the tree reaches 6 or 7 years of age, and 

 the roots penetrate deeper and reach 

 water, growth ceases and the tree is 

 liable to die back. 



The question of shade in Castilloa 

 culture has been much debated. In 

 Mexico there are still three different 

 methods in vogue- The first that was 

 used in the early days of rubber culture 

 was to plant in shade. It is based on 

 an erroneous observation of nature. 

 Castilloa was found in the forests, and 

 as it is a comparatively low tree, it 



was supposed that it required shade for 

 its successful growth. It was also found 

 that, if the seeds were sown in the open 

 without any shade, the young seedlings 

 often failed, or if they survived the first 

 dry season they grew very slowly. On 

 the other hand seeds germinated very 

 freely when sown in shade, and the 

 seedlings grew rapidly, especially in 

 height. The observant planter soon dis- 

 covered, however, that the first year's 

 growth was not continued, and as years 

 went by he found that shade-grown 

 Castilloa developed into fishing rods 

 without any increment in trunk growth. 

 Moreover, the trees were sickly, often 

 attacked by root fungi, and generally 

 very liable to disease. There are still 

 some planters who persist in keeping 

 shade, enjoying the sight of 40-50 feet 

 high whip-like trees, 6-7 years old, but 

 which never will reach a " tapable" size. 



The second system as regards shading 

 is to plant in semi-shade, that is, to leave 

 a few high trees when clearing, expect- 

 ing these to give the rubber trees a 

 certain amount of shelter in the dry 

 season, when the Castilloa has shed its 

 leaves and is exposed to the scorching 

 sun. This method has been employed 

 with a certain amount of success on 

 some plantations, especially where the 

 soil is liable to become hard and baked if 

 exposed to the sun. It seems the most 

 natural, as Castilloa in its wild state 

 always occurs in the vicinity of other 

 trees from which it receives shelter and 

 shade. To establish such conditions it 

 is not, however, necessary to leave 

 jungle trees as shade, but by planting 

 close the commensalism needed will be 

 obtained. This can easily be overdone, 

 and the planter has to exert consider- 

 able judgment in regard to the distance 

 at which he should plant. In localities 

 where the soil Is very moist or drainage 

 imperfect any shade whatsoever may 

 prove dangerous to the health of the 

 rubber, and it certainly will greatly 

 retard the proper development of the 

 stand. 



The third method is to plant in the 

 open. If the seeds are sown at an unsuit- 

 able time, that is, if the soil is not moist 

 or if no rain follows for weeks, complete 

 failure in germinating may result. If 

 the district has a distinct dry season, 

 the seedlings will suffer greatly during 

 that time, in case they have not had a 

 good growth before the rains were over. 

 Otherwise there are no objections to 

 planting in the open, and if this has 

 been done fairly close, so that the 

 young plants partly shade each other, 

 they have under these conditions the 

 best opportunities for a rapid develop- 

 ment. 



