bsequently a very large graft on one medium sized black walnut tree
died, but this was due to injury at the point of union rather than to
the graft above. The remaining scions made a good growth this season.
Seedling trees of another strain of Chinese walnut showed some variation
in their hardiness. Some came through in good condition and made a
vigorous growth but others were more or less injured. The limited number
of trees under observation scarcely justifies definite conclusion, but
it would seem as though this form of Juglans regia is worthy of a wider
trial in southern Michigan.

_Types of Winter Injury_

The following forms of winter injury which have been referred to in the
preceding notes are given special attention hereunder.

(1) Killing back of branches.

This type was found on every tree except the hardy varieties of Polish
and Russian origin. In some cases the large branches were killed
outright, but usually the injury was confined to small branches, and the
degree of injury varied from slight to very severe killing. Branches so
injured were attacked by fungus diseases and some were beginning to
decay and fall off when examined in October. Killing back of the
branches was also noted on one excellent heartnut at Scotland, Ontario.
This tree was subjected to -30 degrees F. but was less severely injured
than many of the English walnuts noted above, and when examined in
September showed a vigorous new growth throughout most of the top. There
were also several vigorous seedlings from this tree growing near by
which were only slightly injured in the bark or which were uninjured. It
was interesting to observe that the seedlings of the old heartnut tree
that were apparently of hybrid origin were not injured in the least and
bore good crops of nuts this year, but the seedlings that were pure
heartnuts were injured slightly. This point suggests the desirability of
crossing the finest heartnuts with the best butternuts to get a
combination of the hardiness of the butternut with the good qualities of
the heartnut.

_Bark Killing_

Bark injury is often found on fruit trees following a severe winter and
is occasionally found on nut trees. It may be due to bark splitting or
to desiccation or both. In severe cases of bark splitting the bark
splits vertically and laterally from the ground up for several feet, but
in milder cases the bark is only split away for a short distance. Where
the bark is loosened for som