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 fifth year we tap fifty per cent, of these 

 trees, selecting the poorest and leaving the best trees untouched. 

 We 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 



about rubber 



ist^ikel am 11 jlly - a " 



from pests, animal or vegetable, in our 

 her rubber plantations. But in endeavouring to find 

 preventives we must first of all be practical. Methods that are 

 impossible to realize in practice are not worth mentioning. 



If we are afraid of leaving the roots of rubber trees in the 

 ground, why do we leave the roots and stumps of the jungle trees 

 when we clear the virgin land for rubber planting ? There are 

 hardwoods which do not decay for a longtime, and during the 

 first few years there is a constant decomposition going on, in the 

 ground and above it, of roots, stumps, branches, and even 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 present 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 trees 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 



