and Magazine of the Ceylon Agricultural Society.— June, 1910. 



571 



tappings with various crude instruments I used 

 at first gave excellent results per square inch 

 of bark tapped. I have recently received from 

 England a series of instruments made from my 

 designs, in which the pricking points, varying 

 in size and length, distributed' on rollers, can 

 be forced into the bark making equidistant 

 punctures all over the surface of the trunk. 



When I have carried on a series of exact ex- 

 perimental tappings with these new tapping 

 instruments and discover which of the pricking 

 points is the most effective, and at what dis- 

 tance the punctures should be made, an account 

 will be published in detail, and it is therefore 

 not necessary hereto go further into the question. 



It would be premature to make any estimate 

 of the quantity of the latex which may be ex- 

 pected from these pricking methods, but results 

 on small areas of bark in one pricking have given 

 yields which when multiplied by the difference 

 between the area tapped and the area available 

 amount to from j to 2f lb. per treeinone tapping. 



It must, however, be explained in connection 

 with these preliminary experiments over a small 

 portion of the area of the tree that it is impro- 

 bable that the whole area will give as much as 

 the multiple of the amount recorded from the 

 smaller area. In the latter some latex comes 

 from an area outside the tapped and measured 

 portion. Mr Smith of Tobago, who has carried 

 on experiments as to this method of tapping, 

 supports this and informs me that a trial of the 

 whole area on a tree in his estate showed a less 

 amount than that obtained from a portion. 



The question as to whether the maximum of 

 latex can be extracted by pricking the whole 

 as against treating a portion, say half or one- 

 third, of the tapped area of the tree is one which 

 must be determined, and in aseries of experiments 

 which I have planned and which will be carried 

 out by the pormission of the owners on six diffe- 

 rent rubber plantations of trees of eight years 

 and older, this problem will, I hope, be solved. 



I hope that such experiments will be carried 

 on by all planters having tappable Castilloa 

 trees, and it will be of much assistance if any 

 carefully recorded data as to yield by pricking 

 or any other process can be sent to me. In 

 order to get the best yields from the pricking 

 method the tree must be occasionally sprayed 

 with water during the tapping process until 

 the latex ceases to flow, this will be found to 

 largely increase the amount extracted, the holes 

 by this means being kept open and the rubber 

 not allowed to coagulate in them and thus stop 

 auy further flow. 



My experience on this point has been that 

 while the flow from punctures properly made and 

 without spraying or watering will flow for some 

 15-25 minutes, if coagulation is prevented by ap- 

 plying water the flow will continue from 50 75 

 minutes and will result in some 30 per cent, to 

 40 per cent, more latex. 



With regard to methods of planting I would 

 strongly advise the planting of rubber by itself 

 on the land and not in conjunction with other 

 trees. Mixed cacao and rubber plantations 

 rarely do justice either to the one or the other 

 cultivation. The rubber should be planted in 

 the open without any shade over it at all, and 

 the method of planting stumps which has resulted 



in such excellent plantation of over 300,000 

 acres in Malaya, will probably be found to be the 

 best here. The stumps used are plants from 

 the nurseries of six to eighteen months old from 

 which the green portions have been cut and the 

 roots roughly trimmed, the result being a stick 

 of about ^ in. in diameter from 4 to 5 feet 

 high. These, when planted in the held in suit- 

 able weather, should strike and produce leaves 

 within a few weeks. 



The field must be prepared for the rubber 

 some months before they are planted ; and if it 

 is virgin jungle, the best method will be directly 

 after it has burnt off to establish by sowing 

 broadcast or by planting whatever cover plant 

 is selected as the most suitable. 



When once the cover plant is thoroughly es- 

 tablished, the field needs no more attention, and 

 when the stumps are ready, and good planting 

 weather is anticipated, they can be put out with- 

 out materially disturbing the cover on the soil. 

 Distance of Trees. 



As to the distance of planting, like most agri- 

 cultural problems it admits of argument. The 

 reasons against close planting, i.e., 12 xl2 feet or 

 closer (302 to the acre) are : That it prevents the 

 tree from growing to full vigour and to the 

 greatest pospible size, forcing it to run up to the 

 light and giving no room for lateral branches. 

 That it increases the cost of collection of rubber 

 since a larger number of trees have to be tapped 

 for the same amount of rubber. That if it is 

 found necessary to give the trees more room the 

 cutting out of a proportion of them is fraught 

 with much danger to the remainder, inasmuch 

 as each dead rubber tree root or portion of root 

 is a potential centre of root disease fungal or 

 insect. To plant more rubber trees than it is 

 intended to permanently keep on the estate and 

 afterwards by cutting out reduce the number is 

 a dangerous policy. All acquainted with diseases 

 in plants will agree that to leave the dead 

 roots in close proximity to roots of living trees 

 of the same species is most likely to encourage 

 root fungus and insect pests. 



If a planter finds it necessary to give more 

 growing room for the branches and leaves of 

 some of his trees, it is preferable to pollard 

 some allowing thom to grow slowly underneath 

 the branches of the un pruned trees, rather than 

 by cutting them out to leave the decaying roots 

 dotted all over his fields. That the admission 

 of sunlight freely as is possible in a plantation 

 of rubber with trees 20 to 30 feet apart is a 

 safeguard against the attacks of parasitic fungi. 



The advantages claimed for close planting 

 are that it gives for first years of tapping a 

 much larger yield per acre. Evidence in eastern 

 plantations point to this being true during the 

 first 4 or 5 years but the additional cost of tap- 

 ping and the probability that this result will 

 not be so marked as the trees get older to agreat 

 extent modifies this reason for close planting. 



I would have preferred to postpone the wri- 

 ting of these notes of rubber cultivation until I 

 had more exact data upon which to base my 

 opinions, but the number of queries with regard 

 to the possibility of rubber in Trinidad and 

 Tobago, both locally and from England, seem to 

 aecessitate some report as to the position up 

 to the present. Our definite knowledge it} atj 



