WEEDING AND CULTIVATION 229 



Mathieu also suggested that systematic root-pruning by 

 means of chankolling would give great benefit to rubber trees. 

 He says: " When the roots have reached the limit of their 

 feeding-ground they cease to spread. They then coil up and 

 form tangled masses through every inch of the ground, till, 

 space lacking, they cease to throw up new feeders." He is of 

 opinion that a partial and light cutting of the roots at the 

 extremity of their feeding-ground revives them to a very great 

 extent. The opening of the ground, he says, causes moisture 

 to penetrate farther, and the roots strike down at once into new 

 layers of soil. Thousands of new rootlets are thus formed. 

 To carry it out he advises the making of a trench i foot deep 

 between the rows of trees, and, say, 10 feet distant from the 

 trunks. Then two parallel trenches should be dug i foot 

 on either side of the first one, but only 4 inches deep, so as not 

 to injure the main roots. 



There can be little doubt but that in the main feature of 

 their contention, namely, the necessity for regular and thorough 

 cultivation, Messrs Baker and Mathieu are clearly in the right. 

 While admitting, however, that root-pruning, once in a while, 

 is attended with great advantage, the constant pruning of the 

 roots every three months advocated seems a very questionable 

 policy. It is more than doubtful if the trees would not suffer. 

 It would appear to be better to prune the smaller roots by 

 chankolling not oftener than once every two or three years, 

 and at other times to fork over the soil round the roots. No 

 doubt occasional pruning of the roots is a great help in the 

 growth of trees, provided a clean cut is made. It has long been 

 the practice to prune the roots of fruit trees, with very beneficial 

 results to the crops. 



On stiff clay soils tillage has a special advantage, not only on 

 account of the loosening of the soil, but from the fact already 

 stated that tillage has the peculiar effect on clay soils of causing 

 the very fine particles to cling together, and thus the soil be- 

 comes a little coarser. Moisture is more easily able to penetrate 

 the soil, and in dry seasons the roots of the plants can draw up 

 the moisture from the sub-soil more easily. 



The question naturally arises, What cultivation can be done 

 between rows of rubber trees planted at moderately close dis- 

 tances? In such cases it is best first of all to thin out all poor, 



