by the Langkat Sumatra, United Sumatra, Sumatra Para, 

 and Amsterdam-Langkat Companies, possess several thou- 

 sands of old or tappable trees. Most estates, however, 

 consist of coffee interplanted with Para, or old tobacco 

 lands planted up with Hevea, during the last two or three 

 years. There are very few estates consisting of Para 

 trees alone, and in this respect Sumatra comes into line 

 with most other countries. 



Most people have the idea that phenomenally rapid 

 growth is to be seen in Sumatra, the Para trees being 

 reputed to increase in girth at the rate of six inches per 

 year. I have certainly seen trees which have grown at 

 that rate when planted alone and on virgin land, but most 

 estates I visited could not generally lay claim to such 

 rapid developments. The well-known Sumatra rubber 

 estates have nearly all been developed out of coffee plan- 

 tations, and the growth of the Para trees thereon is 

 not what it might otherwise have been. Coffee bushes, 

 especially when old, do keep back fEe growth of the Para 

 trees. At the same time they give a crop which enables 

 the directors to pay a dividend from the beginning, or 

 materially reduce weeding expenses during the first five 

 years. The growth of the Para trees is most rapid when 

 planted alone, next best when planted at the same time 

 as the intercrop, and slowest when in old coffee or on old 

 lalang and tobacco grounds. I should put the circum- 

 ferential rate of growth in Sumatra at six, five and four 

 inches respectively, on lands included in the three cate- 

 gories enumerated above. It is very dangerous to gene- 

 ralise in this way, especially when the trees are scattered 

 over the Serdang, Langkat and Asahan districts, but I 

 think the above conclusion will be found to be approxi- 

 mately correct in most instances. 



Effect of Rubber on Other Cultivations. 



On many estates the effect of rubber cultivation is 

 quite obvious. Sooner or later the Hevea and Ficus 

 trees must alone be in possession of the land. As in the 

 low-country tea lands of Ceylon and the sugar estates 

 of Perak, the Hevea and Ficus trees, with increased 

 age, demand more soil. In Sumatra and Java the coffee 

 estates interplanted with rubber will soon be transformed 



