82 PARA RUBBER. 



and re-commenced at 3 to 4 p.m. All-night tapping is of course 

 only possible when the artificial lighting of estates is more perfect 

 than at present. 



In the early and late parts of the day the temperature is 

 lower, the air usually more moist, and there is less transpiration 

 of water from the leaves ; the combined effect of these factors is a 

 better flow of latex during such times. According to Ridley* 

 the girth of the tree decreases during the day and increases towards 

 evening, an observation which may throw some light on the theories 

 regarding tension of the laticiferous tissue and transpiration. 



Ridley also states (Annual Report on the Botanic Gardens, Singa- 

 pore and Penang, for 1904) that the most favourable times for tapping 

 are morning and evening, and from the same number of trees which 

 produced a total amount of 578 lb., the morning trees realized 314 

 lb. , while the evening trees gave only 263 lb. , showing a difference 

 in favour of the morning tapping of 51 lb. Ridley and Derry 

 concluded that evening tappings to be successful should be deferred 

 to as late an hour as possible. 



Compass Tapping. 

 Several experiments have been carried on with the object of 

 proving which is thejbest part of the tree to tap during morning and 

 evening. It would appear that the tapping areas of the trees can be 

 conveniently divided into four parts : one side to face north, the 

 next south, and the other two east and west respectively. Each 

 side can be tapped on a definite system, say once per day, twice 

 per week, and so on, but when the east side has to be tapped it is 

 best to perform the operation in the afternoon or evening, and to 

 tap the west side during the early part of the day. Such a method, 

 applicable to the east and west sides of the tree, prevents direct 

 exposure of the tapping area to the sun's rays during working 

 operations, and allows the flow of latex to continue for a slightly 

 longer period of time. 



Frequency of Tapping. 



The frequency of tapping varies considerably, but it is by no 

 means clearly proved that the tree will not stand tapping every 

 alternate clay throughout the greater part of the year. The fact 

 that an interval of one day is sufficient for the wound response to 

 become obvious is of interest and importance. 



It is perhaps not advisable to judge the effect of very frequent 

 tapping from the results obtained in the Amazon Districts, as there 

 the trees are usually very old and in many cases have never been 

 tapped before. Nevetherless, it is of interest to learn that in those 

 districts the Para rubber tree is often tapped for 180 days continually 

 without apparently doing very serious damage to the trees. 



* Annual Report of the Director, Botanic Gardens, Singapore. 



