PARA RUBBER. 103 



It must be obvious to every one that (lie stripping of the 

 bark, as executed in tapping, is an unnatural process and not 

 exactly comparable with the same phenomenon in nature. It differs 

 from the natural process in so far that the cortical cells are excised 

 while they are in a living condition, and are entirely removed at a 

 time when they contain reserve food intended for the use of the 

 plant ; it also differs from the natural process in so far that the 

 average operator exposes the inner and more delicate and vital 

 tissues of the cortex and cambium to atmospheric influences. 

 Such treatment does affect the vigour of the trees, and if carried 

 out too frequently may hasten the death of the plants. Under 

 these circumstances it may be suggested that the complete strip- 

 ping of the bark, every year, is a forward but dangerous plan on which 

 to work. The writer has seen many trees which are not thriving 

 under such a treatment, and is inclined to recommend it only in 

 cases where thinning-out of the trees is desired. On many estates 

 where the parallel tapping lines or areas arc originally planned 

 out twelve inches apart, the bark can be excised at the rate of 

 one inch per month, which means complete stripping in a year, or 

 an inch may be made to last from two to four months. 

 Excision and Incision. 



If the area is excised at such a rate that the whole of the bark 

 is removed in three years, the oldest renewed tissue, by the 

 time it can again be tapped, may be considered near maturity, 

 and can be operated on with comparative safety. Three to four 

 years is near the minimum time required for the young plants 

 to produce what is considered mature bark, i.e., fit for tapping. 

 The suggestion for less rapid excising is made from a study of 

 the observed effect on Para rubber trees in Ceylon, and it is a 

 question whether it would not be better to only excise the bark 

 tissues when fresh areas are required for the use of the pricking 

 instrument. It is very doubtful whether the paring of the bark 

 should be looked upon as the one and only operation required to 

 obtain a flow of latex ; it might, perhaps, be better regarded as a 

 means of facilitating the collection of the latex obtainable by in- 

 cising and not excising the milk tubes. 



The effect of paring away the outer bark and exposing the 

 internal and more delicate structures to atmospheric influences has 

 in some cases been detrimental. In a particular case in mind 

 the inner tissues dried up and peeled off in flakes, exposing the 

 whole of the wood. This effect is more noticeable on Ceara rubber 

 trees, but is also known to occur on trees of Para rubber. It has 

 been suggested that a covering of some waterproof material or of 

 any substance which, while affording protection from rain or sun, 

 will not harbour insects, might be used to cover the tapping area 

 or renewed bark when collecting operations have been completed. 

 The covering might be arranged loosely in the form of a mantle 

 or be wound round the oblique excised areas like an ordinary 

 " puttie" for one's legs. 



