Pruning Young Trees 81 



be removed. Practically all of the elements that nourish 

 and build up a tree, except carbon, are taken from the 

 soil by the roots in liquid form. This material is car- 

 ried in the cell sap, mostly through the outer sapwood, to 

 the leaves (Chapter V). Here the crude food materials 

 are changed by the influence of the sunlight and the green 

 substance of the leaves to a form that can be readily 

 assimilated by the plant. This will illustrate, briefly, 

 how important the roots are to the plant. 



-Much of the elaborated food may be stored in the cells, 

 especially in the fall, to be drawn upon at any time that 

 the roots fail to supply the requisite amount. In trans- 

 planting, the nursery tree is often deprived of one-half 

 or more of its roots, and not only must it become estab- 

 lished in the soil, but it must produce a large number of 

 new roots before much new food can be supplied. In 

 the meantime, the leaves begin to push out, and the re- 

 serve food and moisture may all be used before the root 

 system is in a condition to supply more. This will explain 

 how newly planted trees may start into growth with ap- 

 parent vigor, only to die later, when the reserve food and 

 moisture is exhausted. By cutting back the tops, and thus 

 reducing the number of buds, this supply is conserved, and 

 thus the tree is tided over the critical time until root- 

 hairs are formed. 



Is it any wonder, then, that the failure to cut back the 

 tops of newly planted trees results in the death of many 

 of them? This is especially true in the arid region, as the 

 dry air and intense sunshine cause the young trees to dry 

 out rapidly. 



It is also true that many nurserymen, as well as fruit- 



