THE CEARA RUBBER TREE 139 



The soil of the district is generally poor, but the tree 

 appears to thrive in such conditions ; in places it was 

 found growing on soft sandstone, gravel, or amongst 

 boulders of grey granite. 



Some further observations on the natural conditions 

 under which the Ceara tree occurs in north-eastern Brazil 

 have been published by Biffcn, who visited the country 

 in 1897. He found the tree growing well under a very 

 wide range of conditions ; on the desert plains where 

 the annual rainfall is stated to be less than 50 in. and 

 the vegetation is scorched for the greater part of the 

 year, and also on the hillsides in poor and rocky soils 

 up to elevations of about 3,500 ft., where the rainfall 

 is probably over 100 in. per annum and the temperature 

 at night falls below 60° F. The tree was never found 

 growing in marshy soil, and it appeared to thrive best 

 in rather scanty soil amongst granite boulders. 



It is stated that hoar frost is experienced at night 

 in some districts of Brazil where Ceara trees occm-, and 

 that they will grow ec[ually well in a dry or humid atmo- 

 sphere provided that the soil is not wet. 



Collection of the Rubber in Brazil. — Ceara trees are 

 usually tapped in Brazil for seven to eight weeks during 

 the year, the tapping being sometimes divided into two 

 periods with an interval between. It is stated that in 

 Ceara the tapping is usually conducted diu-ing the dry 

 season, which extends from June to November. In 

 Bahia the trees occur in two distinct zones, one of which 

 is hot and dry, whilst tlie other is more humid. In 

 the dry zone the best time for tapping is said to be 

 between October and April, whereas in the humid 

 zone September to January is the most favourable 

 period. 



The tapping is performed in a number of ways, of 

 which the following are the most important : 



(1) The soil is removed from the base of the tree so 

 as to expose the roots, and incisions are then made on 

 the roots and on the lower portion of the stem. In some 

 cases only small incisions are made, it being stated that 

 the latex flows better from small than from large cuts, 

 but in others large V incisions are used. The hole in the 

 soil made in exposing the roots serves to collect the latex, 

 and is frequently lined with clay in order to prevent 



