PARA RUBBER. 101 



the rest five and six years, were tapped, and an average yield of 

 } lb. of dry clean rubber per tree for one month was obtained. An 

 estimate of 1 to H lb. of rubber per tree, per year, was given as the 

 probable yield in the future, based upon the above results. In 

 conjunction with this it must be remembered that at an elevation 

 of 2,600 feet in Ceylon, in a relatively dry climate, a yield of 2 lb. 

 of rubber per tree lias been obtained during 1905. 



On the Mergui Rubber Plantation. South India, tapping by the 

 V method was recently carried out, and it was found that morning 

 tapping gave much better results than evening tapping. The 

 figures for the whole season show the average quantity of latex per 

 incision, each 6 inches in length, obtained in the morning to be 

 3*54 c.c. compared with 189 c.c. in the evening. Tapping in the 

 rains was found to give almost double the amount of latex per inci- 

 sion, namely, 6*62 c.c, but the yield of dry rubber per 1,000 c.c. of 

 latex was much less, being 12-8 oz. as compared with 16"4 oz. from 

 morning tapping and 15- 1 oz. from evening tapping before the rains. 

 The best season for tapping was found to be from October to 

 February. 



Yields in The Gold Coast. 

 Four trees, I0}^ears old, were tapped for the first time in 1903, 

 and yielded 4 lb. 3 oz. of dry rubber, or an average of 1 lb. J oz. per 

 tree. Notwithstanding the quantity of rubber extracted, Johnson 

 states that the trees show no signs of having suffered in the slightest 

 degree. 



The amount of rubber yielded by the Para and African trees* 

 may be compared by consulting the tables given below : — 



Number of] Age of Trees, Date of Average yield of 

 Trees tapped, in years. Tapping. Rubber per tree. 



lb. oz. 



Regarding the yield from Hevea brasiliensis, Johnson remarks 

 that it must not be taken as a criterion of the anticipated yield 

 for trees of this age cultivated in West Africa, and points out that 

 the trees referred to are growing in poor, gravelly soil on the top of 

 a hill under unfavourable conditions. 



Estimate of Yield. 

 From these and other considerations it is obvious that to offer 

 an estimate of the yield from trees of known age, one must be conver- 

 sant with the climate and soil conditions, the available tapping 

 area, the trees, and the method and care adopted in tapping 

 operations. The results warrant the conclusion that trees from four 



* Johnson's Report on Rubber in the Gold Coast, 1905. 



