CEYLON 155 



85, 90, 221, 23, 36, 40, run up to from 20 to 40 feet 

 before branching. 



No. 439, the best yielder after No. 2, is one of the 

 smallest trees under trial. The trees of the Riverside 

 Plantation, which gave the highest average yield of dry 

 rubber, have a mean girth of 71 inches, against an 

 average of 89 inches in the thirty-seven-year-old trees. 

 All are large trees, but as far as they go these trials 

 seem to show that after a certain size has been reached 

 increased girth measurement does not necessarily mean 

 increased yield. 



Given room, the trees have extended their roots to a 

 greater distance than their branches. At 55 feet the 

 roots of No. 2 were of the size of a lead pencil and 

 still extending, but they were not visible at the surface. 

 A root of No. i, i inches in thickness, was observed at 

 the surface 60 feet from the base of the trunk. It then 

 descended into the ground. A root of No. 40 outcrops 

 at 80 feet from the trunk. This tree gave 17 pounds 

 5^ ounces of dry rubber in the three and a half months. 



These trials seem to bring out very strongly the 

 importance of giving Hevea room to extend in one 

 direction. It is perhaps reasonable to suppose that 

 had these trees room in every direction even better 

 results would have been obtained; but it is not the 

 object of this paper to attempt to evolve the ideal 

 plantation, but to record facts and to offer suggestions 

 based on those facts. The Henaratgoda trees are 

 particularly happy in not having the issue complicated 

 by subsidiary influences. The soil is poor, the trees 

 have never been manured, the ground is not forked or 

 weeded or grazed. Twice a year the bents are cut with 



