160 THE RUBBER TREE BOOK 



areas, coming into bearing for the first time, do little more 

 than make up for. Under such circumstances more severe 

 tapping and high tapping, which is always bad tapping, have 

 been freely indulged in. On many estates matters have in 

 this way been approaching a crisis, and hundreds of acres have 

 had to be rested on account of over-tapping on many of the 

 best-known estates. This is a proof that a four years' bark- 

 renewal period is not sufficient. Especially is this the case in 

 closely-planted estates. 



On one well-known closely-planted estate in the Federated 

 Malay States the actual rubber contents of the latex from 

 certain areas, as the result of long-continued over-tapping, fell 

 on one occasion to as low a figure as i per cent., a sure proof 

 that the trees were in a very bad condition. 



On such estates, owing to there being no leaves on the lower 

 branches of the trees, the trees therefore being dependent on 

 a scanty crown of foliage, they have not been able to manu- 

 facture sufficient supplies of plant-food for proper bark-re- 

 newal and the natural growth of the trees. The roots of the 

 trees also have been " cribbed, cabined and confined." Owing 

 to the impossibility of cultivation, the soil, among such a 

 tangled mass of roots, has become caked, dank and unaerated, 

 and the bacteria, which ought to supply nitrogen in solution 

 to the roots of the trees, have been unable to fulfil their 

 function, as without proper supplies of oxygen they cannot 

 breathe and work. 



Drastic thinning-out of trees in the endeavour to secure 

 light and air for better bark-renewal is in active process in 

 many estates. Managers and visiting-agents have realized 

 that much longer intervals must be allowed for complete bark- 

 renewal. 



The results of an interesting series of experiments, carried 

 out by the well-known visiting-agent, Mr Skinner, on the West 

 Country Estate, belonging to the Federated Malay States 

 Rubber Company, Limited, are given opposite. 



It will be seen that Mr Skinner experimented with (i) the 

 full-herring-bone tapping on alternate days, giving four com- 

 plete cuts (i.e., eight units); (2) the basal V, daily tapping 

 (two units) ; (3) the basal V, alternate-day tapping (two units) ; 

 (4) single-cut tapping, alternate sides, daily (two units); (5) 



