158 THE BOOK OF NATURE STUDY 



Very little experimental work has been carried out on the 

 effect of the manuring of fruit trees. It appears probable, how- 

 ever, that any excess of soluble plant food in the soil may result 

 in an increased vegetative activity of the trees, accompanied by a 

 diminution in the amount of fruit produced. In fairly fertile 

 soils it would seem that it is sufficient to apply in summer a 

 moderate dressing of farmyard manure. This would supply food 

 to the surface roots just at the time when the fruit is forming, 

 and would also serve to keep the soil moist and cool. Very light 

 soils containing relatively small quantities of available mineral 

 food might be benefited by a spring top dressing of superphos- 

 phate of lime and sulphate of potash, at the rate of one pound 

 of each forked into the soil over one rod of ground round each 

 tree. This would be in addition to the summer mulch of farm- 

 yard manure. 



Apple trees must be pruned. It is only by pruning that the 

 proper shape of the tree is maintained, that the branches are 

 prevented from crossing each other, that the tree is kept open 

 to sun and air, and that the maximum of fruit production is 

 attained. There are two main seasons for pruning, namely, in 

 December, January, or February, and at the beginning of August. 

 If we examine an apple tree in the winter we can readily make out 

 the following points. First, we find long slender shoots bearing 

 numerous small vegetative buds. If we follow the shoot down 

 from the tip we observe a group of rings which marks the position 

 of the bud of the previous spring from which the twig sprang. 

 The portion of the twig which lies between the rings represents, 

 therefore, one year's growth. Below the first group of rings we 

 shall find at a short distance a second group, lower still a third 

 group, and so on ; each portion between two groups of rings 

 representing a year's growth. In this way we can determine the 

 age of any particular portion of a branch. Besides the long 

 slender twigs we shall observe also relatively stout branches only 

 from one to four inches in length, each terminated by a large 

 greyish bud. These are the fruit spurs, and the large buds are 

 bloom buds which will develop fruit. Some of these spurs are 

 natural spurs, others are induced artificially by the pruning. 

 If two shoots are too close together or are growing across each 



