Potassium applications produced the greatest effect on leaf composition, as they increased the concentration of that element in the leaves by 0.285 to 0.760 percentage unit over that in the leaves from the check trees. In addition, it seems likely that this great increase in the potassium content of the leaves was accompanied by a decrease in their magnesium content, since this usually has been found to result. When the ratios of the percentage of magnesium to the percentage of potassium in the leaves were calculated, it was found that they were rather low for the trees that had been fertilized with potassium. The magnesium-potassium ratio was highest in the leaves from the trees fertilized with phosphorus only, followed in order by the check and nitrogen treatments.

Relation of Magnesium Deficiency to Leaf Scorch, Winter Injury, and Fungus Infection

On August 15, 1950, at the time the leaf samples were taken, each tree in the experiment was scored as to the degree of leaf scorch present. In the winter of 1950-51 soil samples were taken from each plot receiving potassium alone and the lime requirement was determined by the Division of Soil and Management and Irrigation, of this Bureau. The lime requirement was found to vary greatly, ranging from 1500 to 6700 pounds per acre. In early spring of 1951, high-magnesium dolomitic lime was applied uniformly at the rate of 1500 pounds per acre and in addition each tree received 5 pounds of Epsom salt.

Each tree in the experiment was scored for degree of winter injury on May 10, 1951. By August 3, leaf scorch was evident on trees in certain treatments and the trees were scored for leaf scorch. At this time it was found in certain treatments that the trees that had not shown any appreciable amount of scorch heretofore had some severely necrotic leaves on them. Careful examination revealed many fruiting bodies of one or more fungi in these necrotic areas. Each tree was, therefore, scored for the presence of this disease, which has been tentatively identified by Paul L. Lentz, of this Bureau, as being caused by Labrella coryli. The data on leaf scorch, winter injury, and the fungus disease are given in table 2.

Table 2. Relation of magnesium deficiency in filbert leaves to leaf scorch, winter injury, and disease caused by Labrella coryli

Trees that had received potassium alone had the most severely scorched leaves and more of them on August 15, 1950, followed by those that had received nitrogen plus potassium. The trees that had received nitrogen or phosphorus alone showed practically no scorch, each having a total score of 1; and the complete fertilizer trees a total score of only 2, while those in the check had a total score of 6. These scores indicate that scorch is related to magnesium deficiency or unbalance. There was a close relation between the amount of leaf scorch in August, 1950, and the amount of winter injury, the coefficient of correlation being 0.97, which is very highly significant. This coefficient means that 94 percent of the winter injury sustained could be accounted for by the leaf scorch present the preceding summer and early fall.

The scorch scores of August, 1951, show that there had been no consistent improvement from the magnesium-deficiency condition as a result of the dolomite and Epsom salt applications. The scores for the disease caused by Labrella show that applications of phosphorus alone increased the incidence of the disease and those of potassium alone or potassium plus nitrogen decreased it.

In all cases, the incidence of leaf scorch, winter injury, and disease were strikingly different on the Reed and Potomac varieties. In the summer of 1950, the total scorch score of the Reed variety was 26 and that of the Potomac 18, and in August, 1951, the scores were 36 and 19, respectively. The total winter injury scores were 46 for the Reed variety and 21 for the Potomac. Thus, it is clearly evident that under the conditions of this experiment the Reed variety was much more susceptible to leaf scorch and to the winter injury resulting from magnesium deficiency or unbalance between magnesium and calcium plus potassium than was the variety Potomac. Furthermore, the total score for the incidence of the disease caused by Labrella coryli on the variety Reed was 38 as compared with 9 for the Potomac variety. It would, therefore, seem that the Reed is about four times as susceptible to infection by this fungus as is the Potomac. Its less vigorous tree growth, susceptibility to leaf scorch, winter injury, and infection by L. coryli may be due to the differences between its nutritional requirements and those of the Potomac variety.

Conclusions and Summary

The preliminary results of the experiment described show that there is a great difference in vigor, growth, flowering habit, susceptibility to leaf scorch, winter injury, and infection with a fungus disease tentatively believed to be caused by L. coryli between trees of the Reed and Potomac filbert varieties. In all cases the Potomac variety has been the superior.

It would appear that much of the leaf scorch on filberts experienced in the past has been due to a magnesium deficiency or to an unbalanced condition between magnesium and calcium plus potassium in their nutrition. The symptoms of magnesium deficiency (scorch), which in general are similar to those on apple and tung, are described. The data presented show that liberal applications of potassium alone, or in combination with nitrogen, resulted in a highly significant increase in the incidence of leaf scorch due to magnesium deficiency. This in turn resulted in susceptibility to winter injury, the coefficient of correlation being 0.97, which means that the severity of the leaf scorch in August, 1950, would account for 94 percent of the winter injury sustained.

Applications of 1500 pounds per acre of high-magnesium dolomite, together with five pounds of Epsom salt per tree in early spring of 1951, did not produce consistent improvement in leaf scorch. It seems that recovery from magnesium deficiency in filberts is slow after treatment, just as has been found to be the case in fruit trees (2, 4).

Literature Cited

1. Boynton, Damon, Cain, Carlton J., and Van Geluwe, John
Incipient Magnesium Deficiency in Some New York Apple Orchards.
Proc. Amer. Soc. Hort. Sci. 42:95-100. 1943.
2.——
Magnesium Nutrition of Apple Trees. Soil Sci. 63:53-58. 1947.
3. Drosdoff, Matthew, and Kenworthy, Alvin L.
Magnesium Deficiency of Tung Trees. Proc. Amer. Soc. Hort.
Sci. 44:1-7 1944.
4.——, and Lagasse, Felix S.
The Effect of Some Magnesium and Calcium Fertilizers in a
Magnesium Deficiency Bearing Tung Orchard. Proc. Amer. Soc.
Hort. Sci. 56:5-11. 1950.
5. Southwick, Lawrence
Magnesium Deficiency in Massachusetts Apple Orchards. Proc.
Amer. Soc. Hort. Sci. 42:85-94. 1943.
6. Wallace, T.
Magnesium Deficiency of Fruit Trees. Jour. Pom. and Hort. Sci.
17:150-166. 1939.

Bunch Disease of Black Walnut

For the past several years observations have been made on the development and spread of the bunch (brooming)[13] disease on Juglans nigra and on other species of walnut growing in the orchards at Plant Industry Station at Beltsville, Maryland. Because of the widespread interest in growing walnuts a brief survey of these observations will be given in this paper together with a summary of the history of the disease and a discussion of its possible effect on walnut production.

History of the Disease

The bunch disease of walnut has been known for years. Waite[14] in 1932 said, "It turned up in Delaware several years ago, where quite a variety of walnuts, including the Persian, the Japanese Group, and the American Black Walnut, were found to be affected. At Arlington Farm, Virginia, during the past 15 years it has boldly riddled the collection of nut trees assembled in the grounds for study and ornamental purposes." Photographs made in 1914 of Japanese walnut trees growing in Georgia and thought to be affected by rosette (now known to be caused by zinc deficiency) have been found in the files of the U. S. Department of Agriculture. Now that the symptoms of the two different disorders are known, it seems clear that the bunch disease was present in those two states at that early date.

Becker,[15] of Climax, Michigan in 1940 reported on his observation of this disease in that area. He reports that he observed several cases of it on Persian walnut, Japanese walnut, and butternut, in addition to many diseased eastern black walnuts. He says, "My conclusions are that in witches'-broom (bunch disease) we have a very bad disease that threatens the black walnut trees everywhere".

In 1939, the late Howard E. Parsons, pathologist of the U. S. Department of Agriculture, made an inspection trip to Climax and other areas in Michigan where he studied and photographed diseased trees. Parsons at that time was working on a similar disease of pecan and

water hickory and was of the opinion that the disease found on the various species of walnuts in Michigan was similar to the one he was studying.

For the past 20 years the bunch disease of walnuts has been under observation by the writers and it seems clear that its incidence has increased greatly during that time. In 1935 scions and buds were taken from diseased eastern black walnut and butternut trees growing at Arlington Farm and grafted or budded on eastern black walnut stock growing in the original nut tree nursery at the Plant Industry Station at Beltsville, Maryland. This was done in an attempt to determine whether the disease was caused by a mineral deficiency or by a virus. All buds and scions died, but the following year two of the seedling rootstocks showed characteristic symptoms of the bunch disease. Since this disease was already present on the station farm it was not definitely known that it was transmitted to the stocks by budding or grafting the diseased material on them.

In December of 1946 Hutchins and Wester[16] presented a paper before the American Phytopathology Society giving the results of their studies on the bunch disease. In this paper they reported that the disease was transmitted by patch bark grafts performed in 1944 and 1945 and that the incubation period varied from several months to two years. It was concluded that since the disease was transmitted by grafting, and in the absence of a visible pathogen, a virus causal agent was indicated.

Symptoms

The characteristic symptoms of the bunch disease are mainly the production of brooms or sucker shoot growth on the tree trunk and main branches and the tufting of terminals, profusion of small branches from axillary buds, the dwarfing and narrowing of the leaflets, and the dying back of the trees resulting sometimes in the death of the trees. The principal symptom is the production during summer of bushy, wiry growth caused by the breaking into growth of lateral buds that normally would remain dormant over the winter. These buds produce shoots that again branch from lateral buds and the process may be repeated for three or four times, resulting in a tightly packed mass or bunch of small, wiry twigs and undersized leaves. Another characteristic symptom is that this growth proliferation continues unabated until the first frost, and, since the wood of these shoots is thus not properly matured, killing back of the diseased portions of the tree usually occurs with the first hard freezes of winter.

As the disease progresses, the wood in the main branches becomes very brittle and is easily broken by wind or ice. This condition is followed by the dying back of branches and finally the death of the tree. Trees even moderately affected soon become worthless for nut production, as few nuts are set and those that mature are usually poorly filled.

Susceptibility of Species

Extended observations show that of the walnut species now grown in eastern United States, the Japanese walnuts, i.e., the Siebold and the heartnut, are by far the most subject to attack by this disease. These walnuts are so susceptible that in localities where this disease is present the planting of young trees is inadvisable, as they are almost certain to be short lived. Once infected, will endanger other walnut trees in the area.

Observations at Beltsville show that the butternut is almost as susceptible to attack as is the Japanese walnut. Some workers are inclined to believe that the rather serious decrease in numbers of butternut trees in some areas is due to the bunch disease. The Persian (English) walnut is also quite susceptible, although probably not so much so as the butternut or the Japanese walnut. The eastern black walnut seems to be the most resistant of all, although some evidence indicates that at least certain trees of this species may have the disease but not show symptoms of it. Gravatt and Stout[17] report that walnut trees may be affected for a considerable length of time without showing recognizable symptoms. Out of a lot of 300 healthy-appearing trees, 37 per cent showed bunch disease symptoms following pruning. Only four percent of the unpruned check trees developed similar symptoms during the same period of time.

Distribution

At the present time bunch disease is quite widespread in eastern United States, occurring in Maryland, District of Columbia, Delaware, New Jersey, New York, Michigan, Ohio, Indiana, Illinois, Pennsylvania, West Virginia, Virginia, North and South Carolina, Georgia, Tennessee, Alabama, and probably other States. No special surveys have been made for bunch disease, and all distribution information has been obtained from observations of U. S. Department of Agriculture or State workers or from specimens submitted.

Damage Caused

Trees with bunch disease may live for several years in a stag-horned or tufted condition. Affected trees generally set few nuts and the nuts that mature are usually poorly filled and hence low in oil content. It is likely that a part of the unsatisfactory growth and fruiting performance of certain eastern black walnut trees may be due to the disease, even though they do not show the symptoms as they are now known. Severely affected trees are subject to cold injury, and in addition the wood becomes very brittle and is easily broken by storms. Although this disease has been known for several years, it is believed that its seriousness has not been fully appreciated, as it does not cause death as soon as symptoms appear. Several years must elapse before the tree succumbs. In the nut tree plantings made at the Plant Industry Station at Beltsville, Maryland, large numbers of butternut, Japanese walnut, and Persian walnut trees were planted. During the following years, although no records have been kept, several hundred of these trees have become affected and have been removed. Consequently at the present time we do not have any butternut or Japanese walnut trees, and only a few Persian (English) walnut trees left in the plantings. So far, not a single eastern black walnut tree has been removed from the orchards because of the bunch disease. Some trees have shown characteristic symptoms of the disease, but following the removal of the entire diseased limbs the symptoms have not reappeared.

Possible Effects of Bunch Disease on the Walnut Industry

This disease is known to spread to nearby healthy walnut trees, but the means by which it is spread or how infection occurs is not known. No survey has been made to determine whether the disease is present in the various regions in which walnut trees are grown, and hence it is not known how widely it is distributed at present. Its spread is probably associated with an insect vector, and the presence of the vector would determine whether or not local spread would occur. Much more must be learned about this disease before its importance and destructive nature can be fully determined. It seems certain that in localities where the disease is already present there is little use in planting young trees of the most susceptible species unless trees in the vicinity that are already diseased are destroyed. Nurserymen growing trees of the Japanese walnut, butternut, and Persian walnut should be sure that no diseased trees which might infect the nursery trees are close to their nurseries. It is not known how far the inoculum may be carried, but at this time it would seem that in order to be reasonably safe no diseased tree should be allowed to grow within a mile radius of a nursery. Infected nursery trees (or scions) probably constitute the most important means of long-distance spread for a disease of this type.

Control

The only known method of control of the bunch disease is to prevent healthy trees from becoming infected. This can be done only by destroying completely all diseased trees. In the early stage of the disease, sometimes only one branch on a tree may show symptoms; and complete removal of this branch may result in the tree's not showing additional symptoms for a year or more. Except in the case of black walnut, the disease breaks out again; hence cutting out diseased limbs cannot be considered a satisfactory control measure, except possibly on the eastern black walnut.

Case Histories at Beltsville

As a part of walnut breeding work carried on during the past 14 years, approximately 20 large nigra trees of named horticultural varieties have been topworked to seedlings of natural first-generation hybrids between J. regia and J. nigra for the purpose of forcing the seedling scions into early fruiting. Of these 20 trees, 3 have shown such unusual behavior as to merit a description of each in the form of a case history.

Tree Number 838. This tree was cut back severely in the spring of 1942, and on August 26, 1943 vigorous new shoots were budded to 47.11-P₁₇, a second-generation seedling of the O'Conner natural hybrid. The buds grew vigorously in 1944 and early in the season developed symptoms of the bunch disease. By the end of the growing season of 1944 the scion limbs were heavy with the typical proliferated shoots characteristic of the disease. Also, a few vigorous sucker limbs of the stock tree that grew out from below the point of union of the scions showed typical symptoms of the disease, although these limbs were later outgrown by normal shoots and are not now to be seen. In the early spring of 1945 the diseased limbs were all removed from the tree to prevent the further spread of the disease in the area.

At the same time that the above seedling was budded in the top of this tree, a large lateral limb of the stock tree was budded to seedling number 40.70-P₁. This seedling originated from a nut of the Ohio variety of black walnut that was only about 1/4 the size of nuts typical of the variety. At the time it was thought that this nut resulted from a cross of Ohio with pollen of the Persian walnut, as it was produced under bag and following hand-pollination. Later growth of the seedling indicated, however, that the pistillate flower was probably pollinated by J. nigra before the bagging occurred, since only J. nigra characteristics have shown up in the seedling. In 1950, one bud of the nigra seedling 40.70-P₁ has almost completely regenerated the top of the tree and no symptom of the disease is evident. By contrast in 1944, almost all of the top of the tree was occupied by diseased limbs, five in number, of the O'Conner seedling.

Tree Number 854. This tree has shown behavior almost identical with that of Number 838, but three seedlings were topworked instead of one. All three originated from the Coye hybrid and all were budded on July 27, 1944. Less than one month later all buds had produced a foot or more of growth, and one to two scions of each seedling reached sufficient size and vigor to survive the following winter without damage. None of the scions branched in 1944, and all failed to show symptoms of the disease. Early in 1945 profuse branching occurred on the one surviving scion of seedling number 39.03-P₂, and by midsummer excessive proliferation of the buds of primary shoots had resulted in the formation of a mistletoe-like growth characteristic of the disease. Scions of the two other seedlings, 39.03-P₈ and 39.03-P₁₁, were lost by wind damage in midsummer, but at the time they showed no signs of the disease. Most of the shoots of 39.03-P₂ were killed during the following winter, and in April, 1946, the remaining live portions were removed by the Division of Forest Pathology for use in transmission studies.

On August 18, 1944, four patch buds of the O'Conner natural hybrid were placed on one of the main limbs of this tree. One of these buds grew, and in 1950 has come to occupy more than half the top of the tree. The remainder of the top is made up of the original stock tree. There is no evidence of bunching in the tree at present.

Tree Number 411. This tree was budded to six seedlings of the Fox natural hybrid on April 28, 1943. Only one of these lived, 40.45-P₄, and one scion of this seedling in 1950 comprises the entire crown. No symptom of the disease has appeared in this scion, and the tree is healthy at present.

On April 8, 1944, small lateral limbs of the tree were splice-grafted to two Coye seedlings, 39.03-P₈ and 41.26-P₁₀. One scions of each grew vigorously during the summer, and 41.26-P₁₀ first became chlorotic, then diseased. Seedling 39.03-P₈ became chlorotic but at the end of the season had not shown symptoms of the disease. Both were removed from the tree early in 1945 and the living shoots used for scionwood in transmission studies by the Division of Forest Pathology.

An additional case is Tree Number 795. This is a grafted tree of the Graham variety of black walnut that was planted in 1932 within 100 feet of trees of the Bates and Faust varieties of heartnuts. By 1940 the latter trees were heavily infected with bunch disease, but it was not until 1943 or 1944 that symptoms were discovered in the Graham tree. At this time the heartnuts were removed from the orchard. The Graham tree has shown only a few small diseased limbs during the past six or seven years, and in 1950 a fair crop of nuts is in prospect.

Discussion

The following observations should be mentioned briefly before discussing the questions raised by the case histories:

It should be pointed out that a considerable number of heartnut and butternut trees were planted at random in the same orchards with the black walnut trees used in these experiments and at the same time (1932). In many cases black walnut trees grew within 50 or 100 feet of the heartnut trees. The bunch disease first appeared on heartnut trees, the most susceptible walnut species, and spread quickly to butternut, which is also very susceptible. By 1940 most of the diseased heartnuts had been removed from the orchards, but it was not until after the top-working experiments described above were completed that the orchards were cleared of all diseased trees. It is therefore possible that insect vectors or other agencies may have spread the disease to the scions of the topworked seedlings from the infected heartnut and butternut trees.

Number 795 is the only J. nigra tree on the station farm that has consistently shown symptoms of the disease during the past eight years, and in 1950 only a few limbs are affected. On the basis of the admittedly meager information reported here, it can be stated that the black walnut varieties used in these experiments are more resistant to the bunch disease than are varieties and seedlings of heartnut and butternut. That this is generally true is also borne out by the fact that in the vicinity of Beltsville, Maryland, and the District of Columbia, practically all dooryard trees of the Japanese walnut are infected with bunch disease, many of them having already been killed, whereas relatively few black walnut trees in the area show symptoms of the disease.

The suggestion has been made that most varieties and seedlings of black walnut are symptomless carriers of the disease, and only under certain adverse conditions of environment would symptoms appear. This would explain why trees that are cut back severely, as was the case with tree Number 838 described above, show symptoms on the excessively vigorous shoots of the next year's growth.

Little can be said at the present time about the relative resistance of black walnut varieties to the bunch disease because nothing is known about how it is spread from one individual tree to another. The case histories of trees described in the present paper are considered to be worth recording because they show that black walnut trees may support diseased scions and later regenerate apparently healthy tops. In these cases the trees showed a type of resistance to the disease. However, there are many cases known, the majority of which are seedlings, in which black walnut trees became so badly infected with the disease that nut production ceased and the trees later died. Whether the type of resistance described in this paper is widely prevalent in the black walnut as a species will be impossible to determine until more is known about how the disease is spread.

WEDNESDAY MORNING SESSION

Today golf club heads are being made of "Compreg," a wood which has been impregnated with phenolic resins and cured with heat. The resin is similar to Bakelite. Thin sheets of wood are glued together to build up the head, rather than using a single solid piece, and it makes a considerably better golf club head. The developments in wood use are progressing just as in many other fields. What the wood specialists are trying to do is to take low quality material and change it over to a form which is suitable for many uses for which high-quality expensive material is now used. The timber buyer now wants a tree of long, clean, bole with few knots, of large size,—at least 16 inches in diameter at breast height. In short, he wants high quality material.

What I am saying may not apply to nut growing. Foresters grow trees for the wood crop, with nuts as a by-product. The first 16 feet of trunk or the butt log is his main interest. It should be completely free of limbs, knots, and other defects for at least 16 feet. You can use the logs above the butt-cut but they usually produce lower grade material.

You have two courses to follow. You can grow wood either in natural stands or in plantations, and the end product is very little different. It is probably easier to grow a high quality tree in a plantation than in the wild. What can be easier than growing a timber tree in the woodlands? It eventually reaches merchantable size and is harvested. Well, nature can do better if you give her help. Your chances of growing a high quality tree to merchantable size are better in the plantation.

About ten years ago Dr. R. W. Lorenz of our Department made a study of 150 plantations growing on prairie soil in Illinois. Thirty-six were walnut which ranged in age from 22 to 75 years. The one thing we had the most trouble with was determining their ages. One day we stopped at a farm and talked to a farmer, and we asked him when the trees were planted. This man said he could tell us the exact day. "I was a young lad and a neighbor drove by and said, 'Yesterday Abe Lincoln was shot.'" So we had the historical records to determine the age of that particular plantation.

These plantations ranged in number of trees per acre from 46 to 330. The number of trees per acre has a direct influence on the size or diameter growth of the timber tree. An eight by eight spacing, or 680 trees per acre, eventually will be thinned to 200 trees per acre. That gives each tree proper spacing for best height and diameter growth.

The trees ranged in height from about 31 feet to 85, averaging about a foot and a quarter in height each year. The average diameters ranged from about 12 inches to 15 inches. Individual trees, however, ranged up to 24 inches at breast height (4-1/2' above ground level). Each plantation had had very little or no care. If some of them had been cared for, or "managed", their owners would have had a better wood crop—higher quality and higher quantity too.

Now, as to the growth in the managed plantations. We believe it is possible to grow 300 board feet per acre per year. Compared with upland oak, walnut exceeded it in almost all growth factors up to 70 years of age and then they were about the same.

Of the cultural practices, the most important is probably pruning. Sawing off the limbs growing on the trunk makes all wood produced thereafter free of knots. When the trees reach about six inches in diameter, one should select those he is going to call "crop trees"—about 200 of these per acre—and spend his time getting them to timber size and quality. The other trees are removed over a period of several years, so that you finally have only the 200 high quality crop trees left. The reason I suggest starting the pruning when the trees are six inches in diameter, is that that is the size of the veneer core left after the veneer manufacturer has turned the log for the thin sheet of furniture veneer. Remove the limbs and improve the quality so you get a 16-foot log free of limbs and knots. That is what the buyer is looking for.

I know practically nothing about growing trees for a nut crop, but we seem to have something in common in growing trees both for nuts and timber. Just a lot of it is "horse sense", with a few rules of thumb based upon scientific principles. You must give the crop trees space, give them plenty of room to grow. In the woods they start to grow in a dense undergrowth. The young trees soon reach a height where they begin to dominate their neighbors. There you pick the straight, thrifty-growing trees for crop trees and favor them in your thinning and pruning operations. Tree density influences diameter growth of the trees. In thick stands, trees are usually small and spindly. So plant a large number to give the crop trees good form, then thin the plantation carefully to make it grow.

Grazing and fire are very harmful to tree plantations. Most of the plantations we studied were grazed. A good many were burned. I don't think nut growers would periodically burn their stands to improve the nut production. It is the same with growing a crop of wood. Once the livestock begin to trample or compact the soil, tree growth slows down and when that happens it makes the tree more susceptible to attack by insects and fungi.

As to marketing trees, let's assume you have some material you want to sell. The one thing you want to know is, "how much is it worth?" That is like me asking you what my house is worth. I understand there are persons here not only from Illinois and Iowa, but from New York, West Virginia, Ohio, and Kentucky. Prices on wood products vary not only from state to state but also within a state as well. The things you ought to know are the sizes and the grades of the timber that you want to sell, since they determine price. Now, there are publically employed foresters available to help you. They know your local conditions. The manufacturer's markets determine what he can afford to pay you.

For example, we organized some walnut marketing pools in Illinois during the war. I suppose a half million board feet of Illinois walnut was sold for gun stock material. One company was buying most of the product of the pools. Later we found that this company had a market for low grade stump veneer. Most of the other companies would mark a half dozen trees for their stumps. This company would buy 35 to 40 stumps. Every buyer looked at the same quality and quantity of material, since the trees were all marked. In this case, however, the difference in markets determined the price the manufacturer could pay.

Another thing that concerns price is what we call "logging chance" or how easy is it for the buyer to harvest those trees. I imagine anyone buying trees in Pennsylvania would have considerably more difficulty in getting them out than he would in Illinois. The differences in equipment and methods used to harvest the trees all have a bearing on the price paid the timber owner.

Hickory is commonly sold for handle stock. Wood for striking-tool handles has a definite restriction in the specifications on the number of rings allowed per inch of growth. The Federal Government grades handles on the basis of growth rate. From 17 to 22 growth rings per inch is specified. Timber buyers don't want logs grown any slower than 22 rings per inch and those grown a little faster than ten rings per inch may be acceptable.

Now, as to determining the trees to sell. I mentioned a 16-inch diameter limit. A few trees smaller than this with logs shorter than 8 feet in length may be accepted if a large quantity of wood is to be sold. It has to be economically worth while for the buyer to harvest and transport the wood, or he can't afford to buy it. Each buyer of course has a different set of specifications. You ought to measure and mark those trees you want to sell and ask the buyers to bid only on those marked trees.

Buyers like to approach the timber owner with, "You have some timber I can use. I'll give you $100 for what I can use." That is the same approach as if I were to offer $100 for your entire nut crop. You would probably say, "Let's weigh those nuts so we will have a basis for coming to an agreement." It's the same way with timber. There are two ways you can sell your timber. You can either measure your trees and sell on a volume basis, or you can mark certain trees and state to several buyers, "I have marked 25 trees for sale. What is your best offer for them?" Each buyer looks at the same trees, and you have a common denominator for comparing the fairness of each bid.

For example, we had a farmer in Woodford County, Illinois who had walnut trees, wild trees, but growing in a pasture grove. I jotted down the bids that were made. One buyer offered $200 for 27 trees, another bid $225 for 35, a third bid $265 for 40 or $165 for 35, and the last buyer offered $425 for 25 trees. The point I am trying to illustrate is that the farmer, without that extremely high bid, would have been unable to compare the bids because someone bid on 27 trees and someone else on 35 trees. If all buyers had bid on 27 marked trees, he would have had a basis for comparing the bids.

Sell on contract. Farm foresters have simple contract forms which they will give you. The forms can be filled out so that they tell what you agree to do and what the buyer agrees to do. Both parties sign the agreement, so there is less chance for disagreement later.

May I have those slides? (Picture showing large tall tree in dense forest.) This isn't a walnut tree, but I want to show you the kind of condition foresters like to see trees growing under. Nice tall stem, free of any limbs, good diameter. These trees show a rather wide range of age classes. When I talk to my folks about growing timber, they say "70 years is a long time to wait for your money." Here is a tree that started 70 years ago and is ready to be harvested. The crop is sustained yield.

I put this in to show you what we don't like to see. (Picture showing park-like stand of timber.) When these 100 or so trees are gone, there will be no others to replace them. Cattle have grazed this stand to the extent that it will be a long time before any other age classes develop to replace those you see in the picture.

That is a white oak. I told you there weren't many. Good diameter all the way up clear of limbs. When the logger cuts that tree he will have high quality material. The same applies for walnut, hickory, or any other species.

This walnut tree shows you how to mark trees for sale. One mark up here so the buyer knows which tree is designated for cutting, and one down at the bottom so you can assure yourself that that tree was to be sold. It identifies one of the trees you intended to sell; a penalty is involved for cutting any others.

I wanted to show you what a good walnut stump-cut looks like. These trees should be 18 inches or larger in diameter at about two feet above the ground to be worthwhile. The stump will be cut off when it gets to the mill, and peeled for veneer.

This is one of the walnut plantations cut for gun stock material. I put this in to show you how the buyers cut the trees down, and measure off the logs to get the best grade of material. They aren't interested so much in volume as in lumber. They want the best grade of wood, and they want it in that butt log.

I put these in to show poor quality logs that weren't worth taking. This is an open pasture grown tree. No care or attention given it, so the limbs stayed on and grew quite large.

This shows how they load logs with a tractor and chain. This "cross haul" is a trick of the logger's trade. This is the improper way. The tractor was broken down so it took five or six men to load it because they didn't have the tractor. There are some good logs and here are some poor logs.

This is a group of logs, at a railroad siding. Some look small, but at that time—with the market as it was—they could use the smaller logs. You see some of nice length, good form and free of defects. I mentioned metal. Here's a man with an Army mine detector. They tried them out to locate metal. This company uses this mine detector to test all logs for metal content.

Here's what happens. The metal discolors or stains the wood. This tree probably grew in a fence line. The buyers are just a little reluctant to buy them. If they do they cut them off this high so they are pretty sure all fence wire is left in the stump portion.

In this grove of walnut a wire is nailed on every tree. Such a practice ruins the tree.

This shows wasteful practice. This small mill in southern Illinois was buying these short bolts cut from small trees. Be careful that you don't sell trees that are too small and too young. It is like, I suppose, harvesting your walnuts before the kernel develops.

This is the result of fire. That log, from outside appearance, didn't have a blemish. Loggers left this part because it was hollow. The infection developed from a fire scar and rotted out the inside.

This shows the same thing. Fire scarred. Bumping machines used to harvest the nut crop or any defect or injury may result in something like this and decrease the tree's value for timber.

I mentioned hickory. Here are some single-trees that are made out of pecan. Hickory is also used. Hickory grows to a commercial size in southern Illinois but in most states it is too small and knotty. One time the Peoria office of the WPB got a release from Washington indicating that hickory was needed for axe handles. They released it to the newspapers. We answered letters for a month after that. Farmers who had hickory they wanted to sell had to be told that there wasn't enough hickory involved to make it commercially possible to market. In addition, there wasn't a single handle mill in the state at that time.

This is a couple of loads of good walnut logs. They were cut in Illinois and trucked to Indiana to be manufactured into veneer and lumber.

Dr. Colby has asked me if I had any methods of getting rid of stumps. We have worked for five years and we still haven't a method that is economical or easy. We recommend grubbing or burning them out with a small stove, or you can cut them close to the ground and let them rot out. What about the chemicals?—We have worked for a good many years and we have bored stumps until our arms ached, but we haven't found any of them that work.

Discussion

MEMBER: 300 board feet per acre per year?

MR. WALTERS: I said we felt that on good soil and by encouraging nature we can grow that volume.

MEMBER: What are the stumpage prices?

MR. WALTERS: Ranging from about $10.00 per thousand board feet to $300. There is quite a span and each grade is different. There is a prime grade, which is the best grade, which must be 16 inches in diameter at the small end at least. Each company has a little different set of grades. Even with the same grade the prices will range according to the size of the log. Maybe a 16 inch prime log may be worth $200 per thousand board feet and 24 inch will be $300.

MR. CRAIG: Curly walnut would be worth more?

MR. WALTERS: Yes. It is somewhat of a guess as to whether a tree will have a curly figure. If you let them take the bark off a tree, the buyers can tell. I know of one beautiful stump on which the buyer wanted permission to remove part of its bark to see if it had nubby growth. If it had had the figure, it would have been very valuable. The farmer said, "I don't want you cutting on that tree because if it doesn't have the figure and you don't buy it, the tree will be spoiled." Don't let the buyers chop into the tree to see whether it has figure.

MR. CRAIG: I bought two to get grafting wood.

[Editor's note: Mr. Craig refers to the Lamb curly black walnut, article on which appeared in NNGA 39th Annual Report.]

MR. WALTERS: There has been some work done on grafting or stimulating growth for figure. One method was to beat the trees with a rubber hose and try to stimulate figured or curly grain. Not too much has been published on this work as yet.

MEMBER: Do you think the figure could be propagated by asexual propagation?

MR. WALTERS: I don't know. I will say this; in forest trees, the inherited characteristics are the things we depend upon. If a tree has curly figure and the seed carries that characteristic, you may see it in the progeny. An acquired characteristic I don't think you can depend on so much.

MEMBER: Is it thought to be acquired or hereditary?

MR. WALTERS: I just don't know whether it is acquired or hereditary.

DR. ROHRBACHER: One thought came to me on this black walnut timber. It's a long pull, and it is one for our posterity. The thought came to be that it is for those of us who are interested in setting up something for our offspring. The plan has been brought out before of using a grafted known name variety of nuts. Plant those, and perhaps those trees as they grow would first give us that wonderful nut which we were looking for.

Symposium on Nut Tree Propagation

Just as I said, every nut grower is a propagator at heart. A little wee paragraph may be a lead to something which would be of quite a lot of value.

This little brief resumé I passed around yesterday, and now this morning I am using my school teacherish techniques in passing around a sheet of paper. There is merely an outline. Pardon me if I insult your intelligence in getting out that outline. As you notice, we start out with the seedling and end with nursery practice. This outline should fit almost any nut species. It should fit chestnut, hickory, walnut or any. I thought it might be best to have a vote as to which one we talk about first, and then we will run down each particular species. I think we should have our panel come up front.

As I said a while ago, we know that practically every person in this room is a propagator. In order that we have this panel conducted in an orderly way, please raise your hand when you speak. I will get the question and pass it to one of the panel members. Which one shall we take up first?

MR. McDANIEL: Let's take the hard one first, the Chinese chestnut.

All right, chestnut. To be systematic, let's talk about seed. Anyone having any difficulty? No trouble at all. Who grows most of the Chinese chestnuts, germinates most of the seed?

MEMBER: I have trouble with rabbits, squirrels, ground hogs.

MR. O'ROURKE: He wishes to know of something to protect his chestnuts.

DR. McKAY: We don't plant in the Fall. I know of one person who uses red lead. We have never used it. I know that has been done. We store our chestnuts in cold storage over the winter and plant in the Spring.

C. S. WALTERS: May I interrupt? We tried 50 chemicals, treating walnut seed with them or putting them on the seed spot after the nut was planted. The squirrels lifted every nut except those that wouldn't have germinated anyway. The rascals knew the difference. We tried allylisothiocyanate—"tear gas." The squirrels would dig those nuts up and when the vapor got too strong they would go away and allow it to evaporate. Within two weeks they would come back—maybe two or three times—before they finally took the nut. We tried cayenne pepper and n-butyl mercaptan—the main ingredient in "polecat essence." We had squirrels all over our test plots, and the only nuts they didn't take were the bad ones.

MEMBER: I have had every other kind of rodent. I found I have to plant in the spring and always in a tin can, with rock wool over the nut.

MEMBER: We have used rock wool; planted in the spring. They will get them any time.

MEMBER: I did the same thing with chicken wire and no squirrels got them.

MEMBER: I would like to ask Mr. Chase if he has planted chestnuts on a quantity basis.

MR. CHASE: We planted them on a quantity basis and as some of you know our nursery is adjacent to a wooded area where you would assume there would be a lot of rodents and polecats, both kinds—four and two legged. I made that statement once before about never having had any squirrel damage. We don't have any trouble. We do not lose chestnuts. We mulch with composted mixtures.

MEMBER. They claim sawdust will help keep them away.

MR. CHASE: On the other hand, a gentleman wanted to get started with chestnut in the Smokies. We helped him get lined up and he planted in beds and these are perhaps a hundred feet long. We mulched heavily with sawdust. The area had been cut over six to eight years ago and had immense piles of sawdust. We mulched with about four inches and some animal got every chestnut out. We never knew what animal it was. There wasn't any evidence on the top. They got every chestnut which was quite a shock to him. I brought this point out that there was danger and he was going to build the bed up high and cover with wire or he was going to get some of this old camouflage netting type and cover that bed for protection both against rodents and early spring frost. He didn't follow through on that so I don't plead guilty.

MEMBER: Does the Chinese chestnut seed have a rest period?

DR. McKAY: For some years we have had a friendly discussion with the Division of Forest Pathology in regard to whether a chestnut seed has a rest period in the same way black walnut, hickory, or some of the others do, and we are not absolutely set in our opinion on the matter. We have the opinion that the Chinese chestnut does not require a rest period. I will tell you that one species, the Allegany Chinkapin (C. pumila) will germinate very readily as soon as it is matured. It will start growing immediately. When you go into the oak species, you have a number like that. They fall to the ground, and put a root into the soil, become anchored, and grow slowly all winter long. We feel that the Chinese chestnuts are of that type. Perhaps the old American chestnut was that way. It fell to the ground in the fall and it sprouted rather promptly within a month or so and grew slowly. Perhaps the Chinese chestnut is not so much inclined that way. We have done this: we have taken them from storage at various times during the winter and planted them, and have never failed to get reasonably good germination. Others have. The results there vary considerably. Perhaps we can't be too sure about the matter. We simply feel that on the basis of what we have seen and observed, they do not have a definite rest period. Many of the failures that have been obtained have been due to poor storage conditions, where the nut started to spoil and perhaps the workers didn't realize it and planted that nut and the nut spoiled immediately. So you fail, not because of the inability of the seed to sprout, but because it was improperly handled and could not grow.

MR. O'ROURKE: Is it not a fact that ... seed has no true rest period as we know it with trees? On the other hand, about 30 days' exposure to low temperature and moist conditions will cause all those seeds to germinate immediately. It may be somewhat the same with chestnut seed.

MR. STOKE: In confirmation, I furnished a man some seed some years ago and we put them in flower pots and they were a foot high by Christmas.

MR. McDANIEL: The growth is normal from the immediate planting, too. You don't get the suppressed growth later, as in prematurely germinated peach.

MEMBER: The chinkapins will often sprout even before they come out of the bur.

MR. CRAIG: I might say this concerning the California Persian walnuts. Take one at harvest and plant it, and that seed will germinate immediately. You hold it in dry storage and plant in the spring and it will come up in a couple of weeks. I speak from experience.

DR. CRANE: The same thing is true with pecan, in west Texas and Arkansas and California. We have lots of trouble with pecans germinating. It is not uncommon to find a pecan germinated with a root as much as ten inches long grown in the hull. If that nut goes through to maturity and becomes dry, then there is an appreciable delay in germination. They won't germinate as quickly. There has got to be a lot of changes in the kernel after they have once dried out and been harvested before germination will be initiated again.

DR. McKAY: In connection with this question of germinating nut seeds of all kinds, we think it is very important to plant the seed in a well aerated medium. I think that is a mistake many people make. If the soil happens to be of a clay nature, it keeps out oxygen and air and the sprout will rot. That is the reason why, when we plant chestnut seed, we like to plant in sand or the same with any nut seed. Coarse sand has a lot of air in it. That nut has a high demand for oxygen.

MEMBER: In the matter of chestnut seed, don't put too many layers of seeds. One is better than two. Even in rather porous soil, they seem to develop gas. Anyway, I found the bottom ones didn't get enough air and they rotted, whereas on top they didn't. It is better to plant a single layer than more.

MR. SHERMAN: What is the best method of treating the chestnut seeds in the fall to prevent the development of weevils?

DR. McKAY: Of course, there are several ways of treating the nuts for weevils. One is the old hot water method. All of us can heat water. We have to heat it to about 120 degrees. So hot, you can't hold your hand in it. Immerse thirty minutes for an average size nut. Now in connection with the spoilage and rotting that is another matter. We believe in harvesting chestnuts promptly, storing them before they dry out. We of course store our chestnuts in cans. Cans with lids and holes punched at either end.

MR. O'ROURKE: Are there any other questions pertaining to seeds?

MEMBER: I would like to caution persons outside the weevil belt about being very careful if you get nuts that may be infested. Leave your nuts in a small jar and you have the advantage of watching the weevils actually emerging. You can pick the nuts out about February, and you can select all the nuts that are sound. Once in awhile a weevil will live through the winter. One thing we should all be thinking about is that the nurseryman has to produce grafted trees in order to fill a demand, and those nut trees must be produced cheaply and he must use methods which are highly efficient.

MEMBER: Has anyone tried to deep freeze?

DR. CRANE: We tried that just this past winter. For a couple of years back one individual had asked us why we didn't freeze them. Last winter we did. We stored three gallon buckets at two temperatures. One at zero and the other at ten degrees below—hard freezing temperatures. Those nuts stayed frozen from early October until the next April. We brought them out and examined them one morning. The first thing we did was taste them. Those nuts we ate when first opened and you could tell them from no other chestnuts. They were nice eating, sweet. We let those chestnuts thaw evenly at room temperature. That evening we examined them and it's hard to describe what the transformation was in those nuts. In the first place was the deterioration that had gone on as soon as the tissue thawed ... They were dripping water. The tissue had burst and the water just flowed. On the other hand, about an hour after they thawed out, when we first examined them just as they thawed out, you would be amazed at how tender they were. They would melt in your mouth. Freezing apparently breaks down the tissue. The tissue is as soft as it can be. Apparently this freezing transformed some of the starch to sugar. The rub is that it won't keep for even two or three hours.

MEMBER: They might keep if you put them in the soil first.

DR. CRANE: The tissue is ruined.

MR. O'ROURKE: We have now decided certain things pertaining to seed germination. Then we are confronted with the problems of seedling versus clonal rootstocks. I do not know whether or not there have been clonal rootstocks selected for Chinese chestnut. I am sorry to have to ask Dr McKay to talk again but he knows more about it.

DR. McKAY: I can only tell you about the experiment we started this spring on clonal stocks of chestnuts. We have just this year's results. Unfortunately we didn't get good results. We took ten seedling trees. We used nursery trees, large five-year old trees, with vigorous root system, ten seedlings, and got from them 20 roots. We took roots the size of your finger with a lot of feeding roots, and we grafted onto those five times four. We took four per variety. We used five varieties of chestnuts, and all five of those each had four pieces and we had ten of those seedlings. We wanted to find out whether any of those ten seedlings would give us a better set of these five varieties than any other trees. In other words, we are trying to get a start on a clonal rootstock. We used a splice graft. We simply took a piece of scion and spliced it right on the end of the root. We had four of those in the bundle, and we had five per seedling and we had ten of them. That made 20 in all. We planted in a cold frame, with cheesecloth covering to keep the temperature from getting too high. Eventually, if this thing works, we will establish a clonal line. We planted those ten original trees but you will be surprised. We can go back to the original tree if we succeed with clonal lines, so a chestnut variety we hope will be grafted on a line of stock that came from that one original tree. Bear in mind this is the method and it remains to be seen whether it is going to work for chestnuts.

The results are discouraging. Only one or two seedlings gave us six or 8 successful grafts on all the five varieties but by that method of trying all five of these varieties on all ten of the seedings we hope to get a start. We will try them again, and we hope to get at least a start that will work. It may be that we will have to start over again. We may want to take ten other seedlings. That is, in brief, our work so far in that direction.

We took it off the ground. We didn't have long enough side roots.

MEMBER: How about mound layering?

DR. McKAY: We tried cutting off at the ground level and mounding up those sprouts and tried to root them, with no satisfactory results. There was just a small amount of rooting.

MEMBER: Did you try layering?

DR. McKAY: One year we did, but with no success.

MR. McDANIEL: I have seen a few layered successfully but it's a little slow.

MR. O'ROURKE: Shall we move to vegetative propagation and consider cuttings first?

DR. McKAY: Just one thing I think ought to be mentioned at this time. We know that even the use of clonal rootstocks does not entirely eliminate variability. All the work that has been done with these Malling apple stocks shows that, as far as apples are concerned. Now we have an idea which, in a crop like chestnuts, may have very far reaching influence and we feel quite hopeful for it. That is growing seedling progenies of certain parent trees. I want to tell you our experience with it. We started our work on breeding and selection of tung nuts in 1938, and we have tested now over 600 parent trees that were especially selected. Out of those six hundred we have released a total of six horticultural varieties, for asexual propagation. But out of those six we have three trees, the seed of which will produce seedling progenies that come very true to the type of the parent tree. One of those released we know as the Lampton variety. It will produce from 95 to 100 per cent of its seedlings, that are so true to type that you can identify them in the nursery. At the end of the first season you plant 95 to 100 per cent of the remaining trees in the orchard and anybody can identify the trees.

In the case of budded trees we have the variability of the rootstocks, which affects the growth. Since that particular variety has been released there has not been one single nut of that variety crushed. Every single seed is grown to tree size, to plant in a new orchard. It has taken us 12 years to reach that stage, but that one variety is probably the most outstanding thing we have. There is a slight variation in the trees but not as much as you have in other trees.

Now, with Chinese chestnuts, we planted seedlings that were grown from the seed of a parent tree at Beltsville. We planted a thousand trees. There were seedlings grown from seed produced by different parent trees. Out of those thousand there wasn't a single one outstanding. Yet in one lot of seedlings which was planted in Georgia, every one of the seedlings grown from the seeds of that selected tree produced such high quality nuts that we haven't cut out a single tree. There just hasn't been any off types. Now we have gone a step further. We had one called selection 7932 which came into bearing very early. We have had those trees grown from seed. The seedling at three years of age produced a pound of nuts, the seedling having the characteristic of its mother. We have hopes that before many years we shall be able to produce parent trees or clonal lines in which the seed taken from those line and planted will give us uniform seedlings.