12 
We fully realize the necessity of plenty of air and light for the 
growing tree. If this is neglected the whole system naturally is 
detrimental. But there is no reason why such an important 
matter should be overlooked. We have presupposed that we have 
to do with intelligent planters and'superintendents, who realize that 
rubber growing on scientific and profitable commercial lines is a 
shade different from -potato growing, as our forefathers practised 
this necessary and honourable industry a century ago. 
On La Zacualpa we thin the rubber stand several times every 
year until the third year, when we have approximately 800 trees 
to the acre. During the fiffh year we tap fifty per cent, of these 
trees, selecting the poorest and leaving the best trees untouched. 
rWe tap heavily, that is, extracting as much latex as is possible. 
A few weeks later the trees are inspected. Those that have suffered 
from the tapping are marked and doomed. If they still yield latex 
they are cut up with numerous incisions, and a few days afterwards 
the scrap is collected and the trees felled. Those trees that promise 
to recuperate are left untouched for four months, when they are 
again tapped in the regular way. After a second inspection they 
are killed. Exceptional trees which do not crowd upon the 
permanent trees may be left to the following, or sixth year, when 
they are tapped with an ultimate view to their destruction. At the 
end of the sixth year we have 400 trees to the acre. 
Many objections have been raised against this method of 
close planting and successive thinnings. The main point in ques- 
tion seems to be whether the cutting out of a number of trees, 
leaving stumps with the roots in the ground, would not be prepar- 
ing breeding places for fungous or interest diseases. I admit that 
there is some truth in this objection In talking about rubber 
planting I am ^ully aware of the many dangers that may and 
most likely will arise from pests, animal or vegetable, in our 
Castilla or other rubber plantations. But in endeavouring to find 
preventives we must, first of all be practical. Methods that are 
impossible to realize ip practice are not worth mentioning. 
If we are afraid of leaving the roots of rubber trees in the 
ground, why do weleave the roots and stumps of the jungle trees 
when we clear the virgin land for rubber planting ? There are 
hard woods which do not decay for a long time, and during the 
first few years there is a constant decomposition going on, in the 
ground and above it, of roots, stumps, branches, and evep trunks. 
Examination will disclose the fact that all of these are affected 
by some fungus or another, and overground parts also by insects. 
Do these presenf any danger to the planted trees ? They certainly 
do, but as long as the planted trees are sound, they are not likely 
to be attacked, and there is hardly any other way of preventing 
disease than by keeping the frees in good condition. One of the 
main factors affecting the health of rubber trees is the drainage of 
the soil. Keep the ground well drained, and the trees will be sound. 
It has been suggested that the ground should be stumped 
before planting, and others have advised digging up the roots 
after the rubber trees have been cut down. This is all very good, 
but if we have to stump the ground in preparing our land, I think 
