298 The Principles of Fruit-growing. 
“Tt will be seen that in this experiment the ac- 
counts nearly balanced at the end or the first year. 
With careful handling this netting will last ten years 
or more; so that the question—will it pay to use 
it?—will depend largely upon circumstances. Judg- 
ing from our own experience the past season, where, 
in testing varieties of fruits, it becomes absolutely 
necessary that the fruit should remain on the tree 
until fully ripe, there seems to be no question about 
the expediency of covering the trees.” 
Top-grafting bearing trees.*—One of the important 
factors in the secondary care of an apple orchard 
is the grafting over of old trees or of worthless 
varieties. It is often asked if it will pay to graft 
trees after they are fifteen or twenty years old. 
The answer depends entirely upon how profitable the 
trees are in their present condition. If they are 
bringing in no return, then nothing can be lost if 
they are grafted; and if the trees are strong and 
healthy, there is no reason why much should not be 
gained. If the operation of top-grafting is properly 
done, the trees ought to be completely changed over 
to a new variety in three or four years. It should 
be said, however, that the careful fruit-grower will 
find out whether his trees are to be profitable or 
not long before they reach the age of fifteen years. 
Trees which have arrived at that age before the 
owner has found out whether they are useful or 
not, are those which advertise an indifference or 
* For advice respecting the top-working of young trees, see pages 234, 235. 
