44 THE VEGETATIVE SHOOT 



ground, prevents the extensive growth which is noticed in youth : 

 the shoots upon aged trees are therefore very short. 



The difference in the general appearance between young and 

 old trees is striking ; so long as long shoots are produced the 

 crown or head remains open and largely composed of long 

 straight branches, but when the formation of short shoots begins 

 the crown assumes a denser aspect. 



In most trees the terminal bud of a shoot usually develops 

 the strongest shoot, the lateral buds giving rise to shorter 

 branches in regular decreasing order from the tip to the base, 

 where the buds usually produce very short shoots or none at 

 all. In the ash and willow, however, the branches on a shoot are 

 much the same size from top to bottom, and in a few instances 

 the branches are short near the tip and base and long near the 

 middle of the shoot In good soil and a favourable climate the 

 branches of trees are longer than where the ground is poor and 

 lacking in moisture or where the- climate is severe. 



Nitrogenous manures and absence of light due to overcrowding 

 tend to the production of long shoots, while the bearing of fruit 

 checks the vigour of trees and leads to the formation of short 

 shoots. 



13. 'Spurs.' — The short branches upon trees often grow very 

 little each year and may take many years to reach a length of 

 even four or five inches. They are readily recognised by the 

 large number of ring-like scars which mark the place where the 

 bud-scales have fallen off each year. Upon fruit-trees they are 

 known as spurs or fruit-spurs, and they need special attention, 

 as it is upon them that fruit buds are most frequently borne in 

 some kinds of trees. 



The formation of a fruit-spur and its development is illustrated 

 in Figs. 17 and 18. 



4, Fig. 19 is a typical piece of a long shoot of an apple tree 

 three years old bearing fruit-spurs. 



The part 1898 is one season old, and grew from a terminal 



