While in California in 1939 I picked up about five pounds of seeds from a hardy tree growing in the Sierra Nevadas in Sonora, also some native black walnuts. These survived a few years but finally were winter-killed entirely, root and all. The Carpathians are never killed out entirely but continue to grow from the root systems, even though they are frozen back to the ground; but the insect and the fungus have destroyed many thousands of the original group of trees so that there are today perhaps between 1000 and 2000 living trees, which sprout up each spring and kill back each fall with clock-like regularity. Among these; However, are a few outstanding varieties which extend some hope that there may be among these survivors one or more trees which resist the butternut curculio and have become acclimated, to such an extent that they do not entirely kill back but only a little of their new growth is killed. These specimens usually are the ones that make a shorter growth during the summer, in fact have more of a tendency to be a genuine dwarf type of tree. Three such seeding trees were known to have sprouted from exceptionally large and very thin-shelled walnuts, which I believe the Rev. Mr. Crath calls the giant type.
I will now summarize and express my own private opinion regarding the future possibilities of introducing the English walnut into such an extreme northern latitude as we are in. First, experiments started thirty years ago, which period gives a reasonable period of time that any man should feel is necessary to devote to giving a species a try-out. Secondly, we have used material from every reasonably known source. Third, persons in charge had a reasonable amount of skill and success with other varieties to have insured success if the material had been responsive. My opinion, for what it may be worth, is that the species is out of its range in this northern latitude, more particularly because it is too tender to fight its own battles as to insect life which attacks it, particularly the butternut curculio. Grasshoppers, leaf eating insects, and worms of different sorts, also attack it more than they do other nut tree foliage. The possibilities of a break in the strong cycle of insect life is a hopeful prospect which we are helping by breeding tens of thousands of toads and frogs. This might allow some, of the more vigorous specimens to acquire sufficient size to overcome this weakness. In my opinion, the climate itself is not the main governing factor which would kill out all hope of raising English walnuts here; but certainly, coupled with the disastrous attack of insect life and susceptibility to blight, these three foes are almost insurmountable. And then in view of the early vegetating habit of these species, there is the possibility that even though you had a hardy tree, immune to insects, you would never get much fruit.
Discussion
DR. MacDANIELS: Remember, the climate up around St. Paul is a bit rugged, and I think that work of that kind is certainly of value to give us an idea of the limits at which we can grow these trees, but I don't think that we have by any means explored the whole field.
In the Morris collection at Ithaca there is a little Persian walnut about the size of the end of this finger (indicating), a very small nut, that was given to Dr. Morris by a consul from the interior of Asia up in the Himalaya Mountains in Tibet, from of an elevation of about 10,000 feet. That little walnut had a hard shell, harder than some of our shellbark hickory nuts, and a bound kernel that I would say was much less promising than many of the nuts which we discard.
Somewhere, it seems to me, in this vast range of material we ought to be able to find some variety or clone of these species that would be adapted to practically every part of the United States. There at Ithaca we have the difficulties with the Persian walnut mainly of winter cold. That is the absolute low temperature that wipes out the trees, now that I have seen them come and go in my place there and in the vicinity. The old Pomeroy strain is killed at about 20 below zero Fahrenheit. It stayed there in fairly good condition up in the Lockport region until the extreme cold of 1933-34. Once the temperatures went down to nearly 30 below zero, except for a small region around the Niagara peninsula, where it hit only 12. Those trees are still there in that little circumscribed area around Niagara, and we saw a picture of one of them in Mr. Sherman's collection. But the Pomeroy trees, I have learned—I haven't seen them myself—were practically wiped out, as were the others, in what was thought to be the protected area along Lake Erie.
I remember the trees on the Whitecroft farm along Keuka Lake. Some of you saw those when the Nut Growers Association met at Geneva. They are on a bench close to Keuka Lake, which up to 1933-34 had not been frozen over for many years. They had grown, produced good crops, were in excellent condition, but that year the temperature went down to about 30 below zero and stayed there for a number of days. The lake froze over, and the trees were severely damaged. A California redwood which was there—had been there for 80 years—was killed outright, and so it goes.
Now, just for these Carpathian strains it seems to me that we have pretty well—perhaps you might say—licked this question of winter cold; that is, at least down to perhaps 30, 35 below zero Fahrenheit, but we certainly haven't licked the problem of early vegetation. That is, it starts out with warm days in the spring, the shoots get about this long (indicating), you get temperature going down to, say, 26, 27, 28, and your shoots are all killed back and you have lost your year's crop. So that's the problem which in the selection of varieties for this northern country, we have got to keep in mind, as I think that's one thing to look for among your Carpathian trees. It's one which will mature its foliage in the fall fairly early and which does not start out too quickly in the spring.
Now, we know there are some that don't start out in the spring, like these Chinese types, but what we want is a combination of short-season, late-starting, winter-hardy walnuts, and I think we can find them if we keep at it.
I didn't start out to talk so long, but I thought that was perhaps a sort of a summary of some of these things which we are looking for.