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It would be interesting, if some of my neighbours would go and 

 do likewise. 



R. Little. 



WHERE PARA TREES WILL NOT GROW. 



By Herbert Wright. 



There is a general impression, especially among persons who have 

 not lived in the tropics, that all para rubber trees require is occasional 

 tropical heat. It is certainly little less than wonderful to see how 

 many trees thrive in the tropics where the soil is of the poorest, but 

 where there is a high , temperature and plenty of water. Heat alone is 

 not, however, sufficient to ensure continuous growth. A high temper- 

 ature of 75 degs. to 85 clegs. F. (average) is favourable to the cultivation 

 of Hevea brasiliensis ; but this alone would be of no value to rubber 

 planters, even though they possessed the richest alluvial or volcanic 

 soils in the world. There are many areas where para rubber trees will 

 not grow, though a temperature of 100 degs. F., and over, may often be 

 registered. Relative uniformity in temperature, absence of frost and 

 drought, and minimum seasonal changes are almost absolutely neces- 

 sary for the successful cultivation of para rubber trees in non- 

 irrigable, tropical lands. 



The difficulty with which vegetation grows, in spite of the 

 advantages of high atmospheric temperatures, in the coastal regions of 

 the area through which we are now passing is obvious to everyone ; to 

 east and west are extensive tracts of sandy deserts and salt-crusted 

 pools ; hardly a speck of green is to be seen for miles, except in the 

 immediate vicinity of water. The natural vegetation, visible to the 

 traveller on board as the steamer passes from Suez into the Red Sea, 

 is miserably poor ; here and there are tufts of stunted, coarse grass 

 and general herbage, suggestive of more than three acres being required 

 to feed one cow. Further inland, where conditions for plant growth 

 appear to be more favourable, one might imagine it possible to come 

 across laticiferous shrubs similar in habit to the Mexican guayule ; 

 but even they are absent from the immense tracts of flat, open country 

 before us. 



Approaching the Rubber Zone. 



To those armchair rubber experts whose knowledge is confined to 

 synopses of what others have done in the tropics, and who have actually 

 wished their friends to believe in the successful cultivation of tropical 

 species in sub-temperate zones, I would commend the course through 

 which the writer is now passing. We arrived at Aden after having 

 spent a few perspiring nights in the Red Sea. The change in climate 

 has been very instructive. If you want to make a city rubber expert 

 realise the differences between the hot damp air in the tropics and that 

 in middle Europe, and thereby impress him with a knowledge of the 

 climatic conditions under which para rubber trees can be, and are 

 really successfully grown, send him to a sun-burnt, barren land. He 

 will feel convinced that he is approaching the rubber zone even though 

 he may designate his imaginary destination otherwise. He will be 



