106 LUTHER BURBANK 



forget that only about two-thirds of the tree is 

 visible, and that the aerial half is not fundamen- 

 tally more important than the subterranean 

 moiety. Yet it is obvious that the root system 

 furnishes the all-important source of supply of 

 moisture and mineral matter, lacking which 

 growth could not take place at all, let alone fruit 

 bearing. 



Of course we cannot get at the branches of the 

 roots to renovate them as we have renovated the 

 aerial branches, nor would they require the same 

 kind of attention if we could. 



There is no danger that a plant will have too 

 many rootlets, for these are the mouths that 

 reach out into the nutrient earth and take up the 

 chemicals in solution that are part of the 

 materials for the building of branch and leaf 

 and flower and fruit alike. But there is danger 

 that the root system may not develop in the best 

 manner, and there is obvious need that the soil 

 into which the roots penetrate should not be 

 depleted of its nourishing properties. 



As to the manner of development of the root 

 system, of course it is too late to make radical 

 changes if we are dealing with an old tree. With 

 young trees just starting growth or recently 

 transplanted much may be done, as will be 

 pointed out presently. But with the old tree all 



