THE PERSIAN WALNUT, ITS DISASTER AND LESSONS FOR 1912

J. G. Rush, Pennsylvania

The year just closing has been full of disasters both on land and sea, though I do not wish it to be understood that I am inclined to be a pessimist on account of these occurrences.

I wish to speak of a disaster which overtook the walnut industry in the northern states. Early in the year we had an arctic cold wave which put the thermometer from 23 to 33 degrees below zero. This cold wave apparently did no injury to the walnut trees at the time but late in the spring it was discovered that the wood cells were ruptured though the buds and bark were uninjured. In cutting the scions in early April the bark and buds seemed in good condition for grafting; but as the time approached to do the work it was readily seen, by its changed color, that the wood was injured, some scions of course more than others. Those that were only slightly discolored were used in grafting. But as time passed the unhappy result came to light that out of about 2,000 nursery trees grafted only one graft grew. After climbing an 80 foot walnut tree to get our scions, and paying a good price for them besides, this was rather discouraging.

This cold wave, which was unprecedented for the time, had wrought other injuries to the nut industry. That was especially to the young trees that were transplanted the fall previous and last spring. The transplanting with a frost injury already was too great a strain on the feeble life of the trees. The consequence was that some of them died outright, and others made only a feeble growth. But where low and severe pruning was practised good results followed and such trees as were established on the original root system escaped the frost injury entirely. The young nursery trees with dormant buds were not affected in the least but made a strong growth of from three to seven feet this last summer.

The intense cold wave was such that some old and young seedling Persian walnut trees were killed outright, and not only the Persian walnut but in a few instances the American black was very much injured; likewise the Norway maple, magnolia, California privet and roses. Also the peach both in tree and fruit.

Now in conclusion let me say, what is the lesson to be learned? First, as to the propagation of the Persian walnut, great care should be taken that only trees that are hardy should be propagated from, as well as having good bearing qualities with a first class nut. Second, after a freeze such as we had last winter, a special effort should be made to save the newly planted tree by close and severe pruning. As, for example, I had a very fine two year old Hall Persian walnut which was referred to me as dead. I cut the tree off about 4 inches above where it was budded on the black walnut stock. It was not long after that signs of new life appeared and eventually it made a very fine, handsome tree. Nature does indeed some wonderful tricks in this respect by which we can learn valuable lessons; and chief of these is close pruning.

Such a cold wave may visit us only once in a lifetime and should not discourage us from carrying nut culture to its highest development. We must not think for a moment that other walnut sections are exempt from similar visitations. They have them in the Pacific Northwest, and in France and Germany.

As regards the walnut industry for Lancaster county or Pennsylvania in general, I am safe in saying that a fair percentage of the farmers are taking hold of it. This is because of the fact that the San Jose scale has practically destroyed all the old apple trees around the farm buildings, and, not wishing to have the building denuded of the customary shade and fruit, nut trees are planted instead. This is in reality the practice prevalent in France and Germany where they utilize every foot of ground to profitable account.

The life of an apple tree is from fifty to sixty years whereas a walnut tree is just in its prime at that age and destined to live for hundreds of years afterwards. Then again the ravages of the chestnut tree blight are destroying the cultivated paragons just as freely as the chestnuts in the forests, which in a few years will be things of the past, thus giving still more room for walnut and other nut trees.

The Northern Nut Growers Association was organized for a grand and noble purpose, that is to stand together shoulder to shoulder to devise ways and means to bring nut culture to a grand and glorious success.

Mr. Corsan: The temperature Mr. Rush spoke of rather surprises me. Last year at Toronto it did not fall lower than 9 degrees below zero. We had summer almost until New Year's and then a very severe winter until April. I didn't notice any evergreen trees killed, but at Detroit, the Bronx and various other places, I never saw a winter so disastrous for killing evergreens.

The Chairman: Not only that but nurserymen all over eastern New England said they suffered greater losses last winter than ever before.

Prof. Smith: I would like to ask Mr. Rush if it would be possible to cut scions by December 1st, so as to escape danger from such great freezes.

Mr. Rush: I really have little experience in keeping scions. This fall I put some in the moist cold earth in the cellar. I think the experiment will be successful because I have known chestnut scions cut in the fall, to be kept under leaves in the grove till spring.

Prof. Smith: I should like to suggest that you try the following experiment; bury them, wrapped up in a gunny-sack or something, entirely underground where they will have absolute moisture and be shut away from the air. I have found that very successful.

Mr. Rush: Sometimes the trouble is they get too moist.

The Chairman: There is a principle here, and we had better keep down to principles as much as we can. That principle is that if the cells of the scions are distended with water a certain chemical process is going on all the while, because a scion is just as much alive as the red squirrel; it is a living organism. Now then, if the cells are a very little below normal dryness the chemical processes mostly cease, and that is better. We have to use nice judgment in avoiding having a scion so dry that its cells perish or so moist that its cells are undergoing chemical processes too rapidly. Our scions are cut, say, the last of November, then covered with leaves enough to prevent freezing and thawing. That will carry scions pretty well through the winter and perhaps is the best way, but we must never forget that in dealing with scions we are dealing with living red squirrels just as when we are dealing with pollen.

A Member: Are the leaves moist or dry?

The Chairman: The driest leaves in the woods contain more water than you think they do. They carry enough to maintain the life of the cells, if they are packed pretty firmly about your scions, and at the same time the scions are still allowed to breathe. I keep them above ground. I put a layer of shingles on the cellar floor, if I've got a bare ground cellar floor, and then a layer of very fine leaves like locust leaves, then a single layer of scions and then a good big heap of leaves over those, packed tight, a good big heap of apple leaves or anything you have at hand. Try it on the basis of principles. It is a complex question. You can't settle any of these questions off-hand. Every man who has had much experience has learned that he needs a whole lot more.

Prof. Smith: Have you had any experience in fixing up a bed of scions like that and putting it in cold storage?

The Chairman: Yes, but you must tell the cold storage people not to let them get too dry. Tell them you want them in moist cold storage, and to keep the temperature about 40.

A Member: We have found with walnuts that if you have the scions too damp they won't keep very long. If you have them just moist enough to hold them you can keep them all winter, maybe indefinitely.

The Chairman: If your cell is full of water the scion will work as hard as an Irishman.

A Member: I find that we have to graft them above ground, in the North, and if they are too moist when grafted they will dry up, but if kept dry they will grow, because they will remain in good condition until the sap comes up in the stock.

The Chairman: Yes, you must choose a position midway between too dry and too moist.

Mr. Littlepage: That is very important; they won't stand dampness.

Mr. Pomeroy: Wouldn't it be well to dip the cut end of the walnut scion in wax to hold the sap?

The Chairman: I am afraid that would stop its breathing. You are dealing with a red squirrel all the while, remember that.

Col. Sober: My method is this: I have a little room about six feet wide with ice packs on both sides and double doors. In that I pack my scions in this way: I take carbide cans made of iron and put damp sawdust, about an inch or so, on the bottom and then I pack my scions in the cans, cut end down, then I put the top on loosely. I have carried them over the second year in that way.

The Chairman: But you let them breathe all the while?

Col. Sober: Certainly, and they have but very little moisture. They are kept in a temperature of about 40 degrees.

Prof. Smith: How often do you wet that sawdust?

Col. Sober: Not once.

The Chairman: Well, that's in keeping with our theoretical basis.

Col. Sober: I cut scions any time between now and March. I don't take them out of storage until we use them. We graft up to the middle of June.

The Chairman: I found some hickory scions that had been accidentally overlooked, kept under leaves, and the buds in the cambium were perfectly good after two years. In regard to winter injury—in the vicinity of Stamford, Conn., the nurserymen reported greater losses of all kinds in nursery stock than they had had before in their experience. I noticed that some small branches of the Persian walnuts had been injured, and particularly where grafts had started a little late and had not lignified quite thoroughly I lost whatever grafts had not had time to lignify. Last winter the injuries in our vicinity consisted chiefly of two kinds; occasional killing of the small branches—this does little harm because, where the branch is killed and dies back for a certain distance, we have three or four more branches starting up, so that perhaps it is not sophistical to say that it does the tree good. We get a larger bearing area than if it were not for this occasional freezing of small branches. Another form of injury occurs in the spring. The sap will start to ascend when we have warm days in February and March; then a few cold days come and, if we have absolutely freezing temperature at night, this sap freezes and when it freezes it expands, as water does everywhere, and the result is a bursting of the bark. That is an occasional happening with all trees but particularly with exotics. One kind of winter injury has been overlooked in connection with the walnut. The very last thing which the tree does in the autumn is to complete its buds for female flowers. That is the very last job the tree has on hand and if the tree cannot complete the buds for female flowers perfectly, then a very little wood killing will make that a barren tree, although it appears to be a good strong tree. That covers the kinds of winter injury I have seen in the vicinity of Stamford, Conn.

(Here Col. C. K. Sober of Pennsylvania showed lantern slide views of his orchards of paragon chestnuts and his methods.)

The Chairman: We will have now Mr. Reed's address with lantern views.