After decay has started, I would suggest—
(1) Cut out all the decayed woody matter, preferably from one side, so that a free and easy drainage of the wound may result. If necessary, when several scions have been placed around the stub, sacrifice one of the grafts and make a rather long oblique cut or groove from which all decayed matter has been removed. Use shellac, liquid grafting wax or melted paraffine over the cut bark, cambium and adjoining sapwood immediately after the final cut is made.
(2) Cover the entire wound with some good preparation to keep out disease germs and water. Preferably use for a covering such materials as will be more or less permanent and which have been found by practical experience to be least injurious and most effective on the particular nut tree that you are treating.
(3) Keep the wound thoroughly painted or covered at all times until it is completely sealed over by a new growth of callus.
(4) If the top-working was originally done in such a manner that the removal of all the decay results in a cavity that cannot be properly drained, it is advisable to fill the cavity with some waterproofing and antiseptic material in order to prevent it holding water and also to assist the cambium in covering the wound. The cavity must first be treated in accordance with approved tree surgery practices. In shade tree work, quite a variety of substances have been used to fill cavities with more or less success; e. g., wood blocks and strips, asphalt and sawdust, asphalt and sand, clear coal tar, clear asphalt, elastic cement, magnesian cement, Roman (or Portland) cement, etc. Of these only two—wooden blocks and Portland cement, have been in general use more than a few years. Blocks of wood were used in France to fill cavities more than 60 years ago, and in this country to some extent about 50 years ago. Later, Portland cement was used in preference to wood for fillings, probably mainly because it was more easily handled. To us of the present generation, Portland cement in combination with sand is the one material that seems to have been in general use sufficiently long to allow us to draw any seemingly reliable conclusion as to its real merits.
For the personal use of the average orchardist, Portland cement is one of the last in the list mentioned above that I would recommend. According to a few reports that have reached me, wooden blocks and tar proved to be fairly satisfactory half a century ago, and strips of wood embedded in some flexible and antiseptic material, are proving very satisfactory today. An excellent preparation to use between the strips of wood, containing asphalt and asbestos, can be readily bought on the market, and it has the advantage of being mixed ready for use. For cavities with horizontal openings that will hold semi-fluid substances, clear asphalt or gas-house (coal) tar may answer all purposes. For cavities with oblique or vertical openings, or for those on the underside of a limb, probably some of the magnesian cements, which readily adhere to wood, will be found more satisfactory when properly mixed and applied.
Although I have said more about filling cavities than of other phases of the work, I do not wish the impression to go forth that I recommend such work except as a last resort, so to speak. The one thing that I do most emphatically recommend above all others is the prevention of decay so far as possible by practices that are less likely to allow decay-producing organisms to gain entrance in the first place, or at any other time.
THE PRESIDENT: Does anyone care to discuss this paper?
MR. KAINS: Mr. President: During the last five years, I have planted several hundred nut trees, including the English walnut, black walnut, the heartnut, pecan (northern ones) and some hybrid hickories. I have noticed that in this nursery stock there has been a good deal of dying-out of the original stock where the trees had been grafted, and where the scion had not covered over. In some of those cases decay has set in, and the trees have died before they could be attended to or have been broken down by the wind. The point is, I think it a mistake for nurserymen to use as large stocks as they have been using in many of these cases, because the stump of the stock is too large for the slowly growing scions to cover over quickly enough. My experience in the planting of fruit trees has been uniformly successful with smaller stocks (that is, trees smaller than I have been able to buy for nut trees) with peaches one year from the bud and with apples not more than two years; with berries and stone fruits, not more than two years. In every case, with the fruit trees, one year stocks have given me better results. First, because they healed over more quickly, and second, because I could cut to better advantage in the trees. In no case have I been able to get nut trees as small as I can apples and peaches. I believe that with the smaller trees amateurs will have better success. I bring this matter to the attention of those men who are devoting their lives to the propagation of nut trees.
THE SECRETARY: The subject of transplanting nut trees was treated fully by Mr. Bixby in his paper this morning and will be treated by Mr. Hicks this afternoon in his address on the subject. Mr. Hicks will give a lecture, illustrated with slides, showing how the larger nut trees may be successfully transplanted.