THE TREATMENT OF THE SHOOT 147 



weight of the crown. The modern practice is to reduce the 

 leading shoot, and thus cause a stronger development of the 

 lateral branches ; these will be able during the course of the 

 summer to send a suflScient supply of nutritive matter into the 

 young stem, which will be able to use it for the development 

 of broad rings of wood. 



The tree may furthermore be injured by removing too many 

 branches, so that the tree will not have sufficient centres for 

 the use of the sap raised by the roots. If the branches were 

 removed bit by bit, growth would not be interrupted. It is 

 the sudden removal of the branches which acts injuriously. 

 Too many of the readily elongating buds near the end of the 

 shoots have been cut away, and this may cause excrescences 

 of the cortex and cambium, which may become centres of future 

 disease. This is the case in a disease to which the gooseberry 

 is very liable. If, in the winter grafting of Ribes Grossularia 

 on Bihes auremii, the stock is too much cleared of its lateral 

 branches, the cortex below the insertion of the scion will often 

 form swellings, due to tube-like elongation of its cells, which 

 may ultimately rupture the bark and prevent the graft from 

 growing on. Similar swellings, which do not, however, rupture 

 the bark, are formed on the spurs of soft varieties of pear ; 

 their formation is preceded here too by a removal of all the 

 buds of the spur. 



If the cambium layer suffers from an excessive supply of 

 water owing to the removal of the lateral branches, the newly- 

 formed annual ring may become interrupted by transverse 

 bands of short soft parenchymatous cells in place of the 

 long and hard prosenchyma, and these bands may extend a 

 good way from the surface exposed by the cut. These bands 

 of soft wood parenchyma loosen the annual ring, and may be a 

 great source of danger if any signs of decay show themselves 

 at the cut end. For this softer tissue is very liable to decay, 

 and easily attacked by fungal growths. Trees which are 

 apparently quite healthy will often show, when sawn across, 

 brown markings in the white wood, very often a complete 

 brown ring of decayed tissue. In splitting the stem longi- 

 tudinally, the raoi'e central axis will split away from the outer 

 hollow cylinder of wood just at this brown ring. Such stems 



