December, 1912.] 



429 



3. Where thinning-out is to be done the trees should be lopped at 

 once and followed by uprooting as labour and conditions prevail. The 

 lopped trees may be tapped in the ordinary way until removed." 



Mr, G. H. Gollbdge of Gikiyanakande, Neboda states :— 

 "Thinning-out is claiming the attention of rubber planters and others. 

 Experiments are being carried out on some estates with a view to 

 determining the various points raised. Considerable time, however, 

 must elapse before any very definite data are available. 



It may be taken for granted that immediately after thinning-out the 

 remaining trees will girth much quicker ; but it is impossible to say how 

 long it will be found necessary to wait before the thinned-out areas will 

 equal the closer planted as regards yield per acre. 



Bearing in mind that it should be our chief endeavour to obtain a 

 maximum yield from each acre, having due and full regard to the perma- 

 nent health of the trees, and the importance of cultivation, it seems to me 

 the question resolves itself into what number of trees a well cultivated 

 acre of land will carry and return a crop of say 500 to 600 lb. dry rubber 

 per annum. 



In view of the immense benefits to be derived from cultivation it is 

 very questionable if the solution will be found in wide planting. 



In the light of present knowledge I would rather have 200 than 100 

 trees per acre, and if I were opening now I think it would be 10 by 16 

 (150-170 trees) or 15 by 15 (180-190 trees). 



Given a fairly free soil and good cultivation, climatic conditions being 

 favourable, I would fear nothing we know of at present in the way of 

 pests, so far as Ceylon is concerned. 



With regard to bark renewal, my feeling is that what cultivation will 

 not do wide planting will not either. 



Of course local conditions have to be considered too, and if the climate 

 were always more or less damp (having in mind the canker disease) it 

 would be necessary to consider wider planting. 



In thinning-out there is some doubt, I think, as to whether the trees 

 will ever be what they might have been had they been originally widely 

 planted, either as regards girth, appearance or yielding powers. 



Then supposing an estate to have been widely planted originally, and 

 tapped from say fourth to fifth year, would it be reasonable to expact the 

 much greater yields per tree in the tenth-twelfth years and onward ? 



To sum up, I think the question of thinning-out is one that should not 

 be rushed in any way. 



I have seen very satisfactory and very promising results from culti- 

 vation, and eliminating all sickly trees which should be removed, it would 

 be wise perhaps to see what cultivation will do for the remainder, pending 

 some reliable data to work on. 



1 have been asked more than once, " What about your 5th-6th renewal" 

 — I multiply by three years (the lowest period for good renewal), and find 

 15 and 18 years. — Answer, " Sorry none." 



Has the rapid paring away of many renewed layers of bark anything 

 to do with the present tendency to seize on close plantiug as the direct 

 gauae of thin renewal ? 



