Points in Grading 8i 



of the requirements of tree life, for if the cover is of sufficient 

 depth, say two feet or more, and especially if of compact 

 soil, it will usually quickly and surely kill the tree. 



No less ignorance is exhibited by those who, when such 

 filling is to be done, leave an unfilled depression or space 

 directly around the bole, perhaps walling it up with brick 

 and covering with wire netting or filling with rubble. In 

 doing this the notion is to admit rain water, and perhaps 

 also air, to the roots. But, while undoubtedly the admis- 

 sion of water and air is facilitated by this device, the need 

 of water and air is much less near the bole where only con- 

 ducting roots are located, than on or towards the ambitus 

 of the crown, where the feeding rootlets lie and the respira- 

 tion is most actively needed. Filhng around the bole is, 

 to be sure, undesirable as it not only clogs respiration in 

 that part of the bole, but, with some species, induces the 

 formation of suckers, which weaken the tree. Hence the 

 precaution of keeping the base of the bole free is a good 

 one, but it does not compensate for the filhng over the 

 feeding rootlets. 



There are three ways of meeting the trouble, if there is 

 a strong desire to save the trees instead of removing and 

 replacing them by others. Where practicable, the filling 

 should be done so as to leave depressions with gentle slopes 

 towards the feeding area of the root system; or better still, 

 the filling should be done gradually, taking if possible 

 several years, and after first thoroughly stirring and fertiliz- 

 ing the ground around the roots, so that the tree may ij^ake 

 new feeding roots towards the surface. 



Or, where deep fillings have to be made and valuable 

 trees are to be saved, the following device may be employed. 

 After the ground has been stirred and fertilized as suggested, 

 an air chamber mav be established bv covering the ground 



