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



PROFESSOR FITTING ON THE 



TAPPING OF "HEVEA" UUBEER. 



Experiments in Java Botanic Gardens. 



We are glad to publish below a good sum- 

 mary of a lecture delivered by Professor Fit- 

 ting of Strasburg on the tapping of Hcvea 

 Rubber— the result of experiments ait Buitenzorg 

 Botanic Gardens, Java, The fact that incisions 

 should not be rotapped till the bark cells and 

 wood are refilled with reserve material '' may 

 not be new to many rubber planters ; but the 

 scientific way the conclusion is arrived at, and 

 all the connected deductions, are well worth 

 studying — especially his caution against the. 

 pricker and the view that the herring-bone 

 method (double better than single) is the best. 



Some 18 months ago a German Professor from 

 Strasburg, Professor Fitting, made some inter- 

 esting studies at Buitenzorg on the tapping of 

 Hevea rubber trees, and an interesting lecture 

 was recently delivered before the Malangsche 

 Agricultural Society by Dr. Th. Wurth on tho 

 results obtained, a summary of which appears 

 in the Cultuurgids. According to Prof, .bitting 



EVERY TAPPING METHOD IS MORE OR 

 LESS INJURIOUS 



to the plant, for by incisions in the bark the 

 transport of the feeding material of tho tree is 

 broken. Both the roots and the foliage play a 

 large rGZeinthe sustenance of the tree. Tho 

 former takes up water, and at the same time the 

 salt therein is dissolved ; the crown of tli9 tree 

 turns the carbon, which is obtained from the 

 carbonic acid gas of the air, into sugar. Out 

 of the salt and sugar the plant forms building 

 material, which for its life and growth is of the 

 greatest importance. It has been shown that the 

 water with its salt mounts through the wooden 

 part of the stem ; the building material formed 

 in the crown of the tree, which must be trans- 

 ported to all parts of the plant, including the 

 root, descends through the bark. Further, it is 



IN THE WOODEN' PART OF THE STEM AND THE BARK 

 THAT THE RESERVE QUANTITIES OF BUILDING 

 MATERIAL ARE STORED. 



Whenever the conduct of the sap is broken by 

 any damage to the tree, then the growth of the 

 stem and root i3 carried on by means of the re- 

 serve store until the damage is made good. Tho 

 Professor demonstrates this conclusively by 

 experiments. If a circular incision reaching to 

 the wood is made, the tree, of course, at once 

 endeavours to close this by the formation of 

 tissues ; if it succeeds, tho sap is carried to the 

 bottom in a normal way and the tree prospers 

 again; if it fails, the roct does not receive its 

 proper share of building material, it pines and 

 cannot fulfil its functions, and finally the tree 

 sickens and dies. In the tapping of a rubber 

 tree such serious wounds are, of course, not 

 made; but the same principle brings about 

 similar results and in the case of an oblique 

 incision, as, for example, by tho fish bone 

 method — the transport of the sap is at once 

 interrupted. The plants sets about restoring the 

 sap transport by forming new tissues. For this 

 the resorvo stocks deposited in the bark and 



wood are first used. Professor Fitting showed 

 that in the entire neighbourhood of the wouud 

 in both bark and wood, the sap had vanished. 

 He, therefore, comes to the conclusion that 



AN INCISION MUST NOT BE RE-TAPPED 



afcer the first tapping period 



UNTIL THE CELLS OF BARK AND WOOD ARF, AGAIN 

 FILLED WITH RESERVE MATERIAL. 



The professor did not stay long enough to find 

 out bow long this takes, but he supposes that 

 more than a year, perhaps even two years, is 

 needed before the now bark can be tapped for 

 tho second timo. 



Thus all tapping methods must be con- 

 demned whereby too large a portion of the stem 

 surface is tapped at the same time, for thereby 

 too much sap-transport is broken, and there is a 

 risk that the root will not be provided with suf- 

 ficient building material. For this reason the 



SPIRAL METHOD, FOR EXAMPLE, SHOULD BE 

 • ABANDONED. 



Professor Fitting advises that a cutting only 

 a quarter of the stem circumference broad shall 

 be first tapped. The tapping of this incision 

 lasts five to six months f first tapping period). 

 Thereafter the tree is allowed to rest for six 

 months. Then begins the second tapping period 

 and at the opposite side of the stem, again fol- 

 lowed by a resting time of six months. The third 

 and fourth tapping follow on the same lines, If 

 it appears in the case of old trees that the latex 

 does not decrease in either quantity or quality, 

 then it is better, instead of making the incisions 

 wider, to shorten the term of rest between the 

 various tapping periods, so that after three or 

 even two years ithe planter comes back to the 

 incision first tapped. We see here that Pro- 

 fessor Fitting emphasizes the necessity for a 

 sufficient surface of untapped incisions. The 

 Professor also utters a warning regarding the 

 suitability of the pricker, for the new bark- 

 formed after prick-wounds contains many stone- 

 cells and few milk-sap vessels. Beside this, 

 the wound tissues swell out, producing an un- 

 even surface, which is a disadvantage in tapping. 

 Professor Fitting thus comes to the following 



CONCLUSIONS : — 



(1) Tapping methods which largely or wholly 

 break the horizontal moving of tho sap-stream 

 from the crown to the base of the tree are to 

 be condemned, viz., the spiral method, the V- 

 shaped incisions without collateral spaces bet- 

 ween, the double fishbone method over the whole 

 stem surface, and the two half-fishbones — in so 

 far as they extend over the whole circumference. 



(2j A sufficient number of untapped, not too 

 small (straight) incisions, mu6t be allowed to 

 stand until tie tapped incisions are again in a 

 state to transport building material (for this, 

 perhaps one to two years are necessary). 



(3) Methods with long cuttings are to be 

 deprecated, as the building material moves only 

 very slowly in an oblique direction. 



(4) Of the various tapping methods the her- 

 ringbone seems to be the best (with four periods). 



(5) The double herring-bone is to be preferred 

 to the single. 



(6) Caution must be exercised as to the suita- 

 bility of the pricker.— L, A C. Express, Ded, 24. 



