THE AFRICAN RUBBER TREE 



179 



the yield was much better in October to December than 

 in February to April, whilst tappings in June also gave 

 good results. It is concluded that in the Gold Coast the 

 best time for tapping Funtumia trees is from June to 

 December or January, which includes the period from 

 about the middle of the rainy season to the commence- 

 ment of the harmattan. 



The total yield of rubber obtained in these experiments 

 extending over thirteen months was 31 lb. 15 oz., equal 

 to an average yield of only TBI oz. per tree, which is a 

 very small retm-n. 



III. In another experiment in the Gold Coast, twenty- 

 five trees, 15-| m. in average girth, were tapped six 

 times during eleven days by a herringbone system in 

 March 1911, and gave the following results: 



Dry rubber in grams 



The total yield was 1,467 grams (51^ oz.), equal to 

 206 oz. per tree. 



Southern Nigeria. — I. A series of tappmg experi- 

 ments on Funtumia trees growing in the Mamu Reserve 

 was carried out by the Forest Department in December 

 1909. The half- herringbone, full-herrmgbone, and spiral 

 methods were tried, and also the system of making a 

 number of straight vertical cuts down the stem. The 

 results obtained are summarised in the following account : 



(a) Ten eight-year-old trees, 22' 6 in. in average girth, 

 which had not been tapped previously, were treated by 

 the half-herringbone system, the vertical channel bemg 

 10 ft. long and the lateral incisions 6 in. apart. After 

 the first tappmg the trees were allowed to rest for a few 

 days and were then tapped four times on alternate days 

 by making fresh lateral cuts below the previous incisions. 

 The yields of fresh biscuit rubber were as follows : 



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