2&9 
It would be interesting, 
do likewise. 
if some of my neighbours would go and 
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 degs. 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 m non- 
irrigable, tropical lands. , . , ,, 
The difficulty with which vegetation grows, in spite ot 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 bea, 
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 latieiferous 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 ot 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 Bea. The change in climate 
las been very instructive. If you w T ant to make a city rubiei exper 
•ealise the differences between the hot damp air m the tropics and that 
n middle Europe, and thereby impress him with a knowledge of the 
dimatic conditions under which para rubber trees can be, and aie 
■eally successfully grown, send him to a sun-burnt, barren land. He 
,vill feel convinced that he is approaching the rubber zone even though 
le may designate his imaginary destination otherwise. He will be 
