2 



[Jan. 1907. 



GUIV1S, RESINS, SAPS, AND EXUDATIONS. 



Para Rubber: Distance and Jnterplanting. 



By Herbert Wright. 



On a previous occasion the subject of distance in planting, in connection 

 with Hevea brasiliensis, was discussed, and a certain amount of interest has since 

 been displayed in the subject. It appears necessary, however, to discuss this matter 

 in detail, and to definitely state that I am not in favour of close planting any more 

 than I am in favour of the wide planting of Para rubber trees ; any misconception 

 is no doubt due to the brevity of my original remarks. In the original discussion 

 the advantages and disadvantages of " close planting and thinning-out" were briefly 

 given, and the pros and cons of other possible systems require to be dealt with. 



In the planting of Para rubber there are approximately five systems which 

 may be mentioned : — 



1. Close planting— permanent ; 



2. Close planting and thinning-out ; 



3. Wide planting— permanent ; 



4. Wide planting with catch and inter crops ; 



5. Interplanting with herbaceous and arborescent plants. 



What is Close Planting? 

 To define close planting is a difficult matter, and though actual figures may 

 be quoted, they are subject to modification according to the physical and chemical 

 properties of the soil, and the nature of the climate in which it is proposed 

 to grow the plants. The term — close plantiug — admittedly implies the planting of 

 the trees at a distance which is not sufficient to allow of the full development 

 of all parts of the plants ; the latter is determined by the natural vitality of 

 the plants and the nature of the soil and climate. Medium-distance planting 

 in a poor cabook soil, or in a washed out clay, above 2,500 feet in Ceylon, would 

 be regarded as close planting in a rich alluvial soil in the low country of the 

 same island. The trees should be plauted at such a distance that they will 

 rapidly develop and take possession of the whole of the soil ; their develop- 

 ment is controlled by the amouut of food which the soil supplies, and it is 

 generally conceded that the better the soil, and more forcing the climate, the 

 greater must be the distance allowed. A typical case is to be seen at the 

 Experiment Station, Peradeniya, where some four-year old trees, all planted 15 feet 

 apart, have overlapped their branches on the fiat land, but on the upper part of the 

 hill the spread of the branches is hardly a yard on either side ; by the time the latter 

 have taken possession of the soil the former will require considerable thinning out. 

 It has been argued that if the soil is poorer the trees should be planted at wider 

 distances in order to allow a larger area from which the plants can obtain 

 food ; this is a contention that loses sight of the necessity of quickly placing the 

 plants in possession of all the soil, 



Disregarding the differences in quality of alluvial, cabook, swampy, forest, 

 and chena land, from sea-level up to 3,000 feet in Ceylon, a,nd the allowances to be 

 made according^, it may be generally stated that on a soil similar to that at Pera- 

 deniya, a distance of ten feet apart, or less, for trees of Hevea brasiliensis, may be 

 designated as close planting, one of fifteen feet apart as medium distance, and one 

 of twenty feet apart or over as wide planting. These distances are subject to 

 modification according to local conditions, and are here given only to provide a basia 

 for comparison. 



