228 NEBRASKA STATE HORTICULTURAL SOCIETY. 



liable. Only such seedling stocks will produce trees of certain hardiness. 

 Other seedlings whether from France, Vermont or Kansas will never 

 prove perfectly hardy and should not be used as budding stocks in such 

 states where the winters are often so severe on our fruit trees. The 

 reason for these trees not being hardy is this. In budded trees the roots 

 lie almost entirely in the "danger zone," by which I mean the uppermost 

 layer of soil. I have given this term to the top five or six inches of soil 

 where the most severe freezing and the most drying out takes place, also 

 where often a lot of alternate freezing and thawing takes place. In this 

 so-called danger zone the conditions are the most severe and any root that 

 is not perfectly hardy will die if it lies in this zone. This shows how 

 most of the roots of a budded tree lie in the danger zone. Sometimes the 

 wise orchardist will plant his trees 4 to 6 inches deeper than they had 

 stood before to get the roots out of the danger zone. By this means a 

 lot of winter-killing may be averted. 



But now if a tree is budded on a hardy stock then the tree will survive 

 even the most severe winters, even though the roots are mostly in this 

 danger zone. The danger zone is really only dangerous to the half hardy 

 or tender root. 



WHOLE ROOT GRAFT TREES. 



As far as hardiness is concerned whole root graft trees are very sim- 

 ilar to budded trees. If a hardy root is used in producing the tree then 

 the tree will be hardy. But if, on the other hand a tender root is used the 

 tree will succumb during the first test winter for the roots of a whole root 

 graft tree are also mostly in the danger zone. The only real difference in 

 the whole root graft trees and the budded trees lies in the process of pro- 

 ducing the tree, or ennobling it, as the Germans call it (Veredlung). 



PIECE-ROOT GRAFT TREES. 



In Minnesota the general method used in producing apple trees is the 

 long-scion short-root graft method. This seems to be a kind of graft that 

 had developed through necessity. Piece-root grafts were usually about 

 two-fifths roots and three-fifths scion, but in the grafts now made the 

 scions are from 6 to 7 inches long and the roots from two to two and one- 

 half inches. These are then planted so deeply that only the top bud ap- 

 pears above the surface. In this way the root, even though it should be 

 tender, will come below the danger zone and will not die half as easily as 

 budded or whole root graft trees. Figure 3 shows this long-scion-short- 

 root graft in relation to the danger zone of the soil. 



Such grafts will usually throw out roots from the scion and thus the 

 tree will gradually get onto its own I'oots. It is a great advantage for a 

 tree to be on its own roots because these roots are just as hardy as seed- 

 ling roots from this tree. If the tree is of a hardy variety such a tree will 

 be strictly hardy if on its own roots. If such a tree is not on its own 

 roots then of course the hardiness of the tree will be dependent upon the 

 hardiness of the root or the depth of the root in the soil. That is if the 

 root Is not exactly hardy, it may still survive if the roots have been placed 

 out of the danger zone. 



