286 SCIENCE PROGRESS 



it is remembered that the life of the tree depends on the 

 formation of new roots, not on the preservation of the old ones. 

 Each item of damage and of supposed bad practice in planting 

 trees has been made the subject of separate experiments. 

 The general result of these has been to show that a certain 

 amount of damage to the roots is actually beneficial. It is 

 not very difficult to see the reason of this, for such damage 

 generally results in the new roots being formed from the 

 thicker and stronger parts of the old roots where the store of 

 reserve food is greater, so that the new roots develop more 

 vigorously. Thus, we have found the shortening of the old 

 roots to different extents to be of some slight advantage, so long 

 as not more than one-third of the whole length is removed : 

 greater shortening is detrimental. In the same way, the 

 removal of all the smaller roots of a less diameter than 2 mm. 

 is found to be beneficial (plums and pears were investigated) 

 but loss in vigour has followed the removal of those up to 

 4 mm. Most of the smaller roots, under ordinary conditions, 

 become too much dried up to recover their functions after 

 the tree has been replanted, consequently they die off: this 

 has been fully established by marking these roots by tying 

 pieces of silk round them and lifting the tree again at the end 

 of the first season : it is easily intelligible, therefore, that the 

 tree will be benefited by the removal of rootlets which in any 

 case will decay. Nothing more futile can be imagined than 

 the way in which gardeners carefully spread out and tend 

 these fibrous roots which are already virtually dead. However, 

 the store which is set on a tree which has a mass of fibrous 

 roots has this justification, that if a tree has sent out a good 

 mass of roots while in the nursery it is probable that it will do 

 so again after replanting in the orchard. 



That the spreading out of the main roots and avoidance of all 

 injury has any beneficial effect has been disproved by actual 

 trial. In some cases trees were planted with their roots bent, 

 twisted and tied together tightly in a ball under the trees, 

 whilst in others the roots were lacerated to an extent far in 

 excess of any probable accidental laceration. It was found that 

 the number and vigour of the new roots formed was practically 

 unaffected by this treatment and that there was no detrimental 

 effect on the tree ; even slight benefit accrued in some cases. 



Another point in which accepted rules find no justification in 



