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[December, 1912. 



THINNING-OUT HEVEA ESTATES. 



Opinions of two Ceylon Planters. 



The India Rubber Journal publishes the opinions of two leading 

 planters of Ceylon on the subject of thinning-out of Hevea plantations. 



Mr. W. Newburgh Tisdall says :— 



" I believe the best number of permanent trees per acre to be 100 or less 

 on flat land ; on steep land this might be modified, and up to 150 may not be 

 too many. 



2. My own ideas just now are as follows : 



Clearings planted 10 ft. by 10 ft. I would first cut out alternate rows 

 complete, and later on alternate trees, making 20 ft. by 20 ft. 



12 ft. by 12 ft. I would treat in the same way at first, only cutting 

 out alternate trees if found necessary. 



20 ft. by 10 ft. Cut out alternate trees. 



15 ft. by 15 ft. and 17 ft. by 17 ft. I think might be treated differently, 

 and alternate trees in alternate rows cut out for a commencement. 



I have been thinning-out on various estates, but only so far on very 

 closely planted fields. I found after about three months, where a 10 ft. by 

 10 ft. field had alternate rows removed, that the foliage of the remaining 

 rows had closed overhead, leaving matters as regards light almost as bad 

 as before. 



3. I believe it would be better to remove the tree, root and branch, at 

 once if labour permits, as if it is necessary to thin out at all it should be 

 done properly. Of course a certain quantity of latex can be obtained 

 from the stump after it is pollarded, but I consider that root development 

 is as great a necessity as light and air. 



After experiment on a certain estate in South India I decided on this 

 course over a field of 242 acres, as it was found where the trees were only 

 pollarded that the other trees did not increase in yield, but where they 

 were removed altogether the other rows showed a decided increase, but 

 noching appreciable until about six months, when the roots doubtless had 

 time to develop; if this experiment can be relied upon, there is no doubt 

 that it is better to remove the slump as soon as possible. 



At the same time I believe that annual doses of a suitable manure 

 will obviate the necessity of cutting out for some time longer. 



The chief danger in not thinning-out is disease, which 1 regret to say 

 has forced itself upon our notice recently. 



I daresay the following opinion will also interest you, It comes from 

 an experienced planter in this district whom you know quite well :— 



1. 100 trees per acre. 



2. Every alternate row it growth fairly even, otherwise backward 

 trees only. 



