48 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



penetrate into the cankered part for shelter is likely enough. 

 Indeed, I can assert they do ; but they are not there as the cause 

 of canker, but because the cankered part affords a secure resting- 

 place, which the smoother, healthier portion of the bark does 

 not. Indeed, I can also assert that cankered trees may be found 

 in the garden with insects upon the affected part, and others 

 near them also cankered with no insects upon them. 



My contention is that canker is caused in two ways, and 

 affects two different parts of a tree. Perhaps the most serious 

 disease is that which affects the trunk or larger branches of the 

 tree. This I hold is caused by the roots pushing downwards 

 into cold, undrained, or unsuitable soil. The other aspect of the 

 disease is that which lays hold of the twiggy portion of the tree, 

 for even the one-year old shoots do not escape. The immediate 

 cause of this is probably owing to the rupture of the sap vessels 

 by frost, when the sap is in an active state. But I have a firm 

 belief that the primary cause is to be found in the condition 

 of the roots, which, being in an inactive state owing to unsuitable 

 soil or their penetration to a great depth, prevents the perfect 

 ripening of the wood, or maturation of the blossom buds in the 

 autumn. 



I come now to my own experience in our old garden twenty- 

 five years ago. There were upwards of one hundred trees of 

 various sizes, some only a few years old, others a hundred years 

 planted at least. Most of them were cankered, and in places 

 where the old trees had been removed and young ones planted, 

 canker showed itself in a few years. 



The soil was light, over a gravel subsoil, and was naturally 

 drained ; the water did not stand on the surface for any length of 

 time, even in very wet weather. I was confident that want of 

 drainage had nothing to do with it, and that the fault was in the 

 cultivation. Young trees seldom do any good planted amongst 

 old ones, even if the soil has been well dug up and enriched with 

 manure where the roots are to be placed. They require a wider 

 and better field for their ramifications. I found I had to make 

 gravel paths as well as fruit borders, and as most of the old trees 

 were on the wane, and the young ones of but little value owing 

 to their cankered state, it was thought best to remove them. 

 But they were not all removed at once, as it was necessary to 

 keep up a supply of fruit for household use. A space about 

 thirty feet wide was lined off through the whole length of the 

 garden, and was cleared of all trees and bushes. In the middle 

 was a space six feet wide for a gravel path. The borders on each 

 side, about twelve feet wide, were trenched, where possible, two 

 feet deep, and we found the gravel cropped up in places within 

 a foot of the surface. Where this was the case the gravel was 

 taken out and used to make the path, the soil from the path 

 being used to fill up the space from whence the gravel was 



