a warm spell of a week or ten days or even shorter, sap will rise
in the trees, and they will start to grow.

MR. STOKE: Not all. In plants of some varieties new growth will hardly
start.

DR. MCKAY: Perhaps you may have varieties that will not start, but the
tendency is to start.

MR. STOKE: If you have one with that early tendency, cut it out.

DR. MCKAY: I'd like to get back to this opinion here on the question of
frozen ground, dormant roots and the effect it has on the top of the
tree. Now, how about our academicians over here, Dr. MacDaniels or Dr.
Crane. Let's hear from one of you.

DR. MACDANIELS: It is my opinion that with a walnut tree of good size
the frozen ground would have little or no effect on the buds starting
growth. The twigs and the trunk would warm up to the temperature of the
air, and when that happens growth occurs. Water is available from that
in the trunk and the deeper roots. This would happen regardless of how
the surface roots were treated.

DR. MACDANIEL: Or whether the tree had any roots on at the time.

DR. MACDANIELS: The best solution to the frost damage problem is to find
trees which vegetate late enough to avoid the spring frosts. Somewhere
on this terrestrial globe there must be some, because I remember years
ago J. F. Jones sent out some Persian walnuts of Chinese origin. I
planted three, and they did not start any growth until about the first
of July, and they were still growing strong when frost hit them in the
fall. Now, somewhere in between these extremes, somewhere in the
climatic analogue of our region we will find Persian walnuts which will
have a delayed vegetating period, and that will be the final answer. At
least, I think so.

DR. MACDANIEL: I'd like to ask a question. In F-2 hybrid walnuts do you
find much segregation of those for later initiation of vegetation?

DR. MCKAY: Yes, we find in those seedlings in some cases the tendency to
vegetate very early and others very late. The most striking case that I
know is an F-1 hybrid which is a very, very late starter in the spring.
It is perfectly dormant when the other young walnuts are in practically
full leaf. We do not have any offspring from that particular one yet,
but it gives us some hope that from this hybrid we may get something
later.

MR. BECKER: With us I don't think this early vegetation means anything.
We are in Michigan. Dark, cold weather continues until about the middle
of May, when frost ends, and