BY-LAWS (continued 2)

Introduction

The Chinese chestnut, Castanea mollissima, now dominates interest among well-informed chestnut planters of the eastern United States almost to the exclusion of other species. Since its introduction in 1906, it has had but one important competitor, the Japanese chestnut, C. crenata. Among the world's most important producers of tree chestnuts, only these two species are effectively resistant to blight. However, the Japanese chestnut lacks the palatability to which Americans are accustomed and for all practical purposes it has been rejected in this country. Many small plantings still survive; but this species serves better for shade and ornamentation than for food production.

Description of the Chinese Chestnut

The nut of this species is usually of good size, roundish in form, not pointed at the apex, and with the basal scar smaller than the lower end of the nut. A certain amount of gray down is on the surface. This down may be confined to a small area about the apex or it may cover much of the upper end of the nut, and it may be thick, thin, or scant. The nut may have good cleaning quality, meaning that the kernel and its pellicle are easily separated. Cleaning quality may be good from the time the nut falls from the tree or it may become so only after curing for a time. Once it develops it may remain good as long as the kernel is usable or it may last for a short while only. In texture and in palatability, the kernel of the Chinese chestnut is not excelled by any other true chestnut. Individual nuts are sometimes sweet from the first but the great majority become so only after being cured for a week or 10 days. Very few nuts of the pure species fail to be sweet when fully cured.

In the open the Chinese chestnut tree attains much the same size and general proportions as does the apple but it may become somewhat larger, more upright and considerably taller. Young seedlings vary greatly in form and are often ungainly and unsymmetrical; but others are all that could be desired with respect to symmetry. Early lack of symmetry tends to become less objectionable as the tree grows older and is seldom conspicuous after the first decade or so.

In fruitfulness, many of the seedling trees of bearing age are definitely disappointing. Also in many cases the nuts are small. To judge the species by the past fruiting performance of a majority of its representatives in this country would leave little justification for commercial hope. However, there are a good many individual trees about the country whose performance record is excellent and a large number of these are under careful observation as potential varieties.

The species has gained rapidly in popularity since the middle 'thirties when enough good-performing trees began bearing for a fair appraisal of the species to be possible. It was also at about that time that trees for planting began to be available from the nurseries. Before then trees could only be had in limited numbers from the Department of Agriculture. Today, they are listed in nursery catalogues of one or more firms in each of a half dozen or more states. The total number of trees yet planted is comparatively small and both nurserymen and planters up to this time have proceeded cautiously because of the newness of the industry and its uncertainties.

Environmental Requirements

The Chinese chestnut requires much the same conditions of climate soil, and soil moisture as does the peach, but there are indications that it will succeed somewhat farther both north and south. As with the peach air drainage must be good and frost pockets must be avoided, for while at the latitude of the District of Columbia, the flowering period is from late May until toward the end of June, growth begins early and may be badly damaged in April. This is especially true during such seasons as those of 1945 and 1946 in the middle Atlantic States when summer temperatures prevailed during a great part of March, and new shoot growth up to two inches had developed when sub-freezing temperatures killed all new growth and so injured the buds that at Beltsville, Maryland, and general vicinity there were no crops in either year. In some cases young trees were killed out-right as were occasional older trees that had become devitalized in some way.

Young trees are so sensitive to lack of soil moisture that sometimes whole plantings are killed by drought. Spring growth is rapid as long as the soil is moist but root development is shallow during the first few years and, unless watered, trees are likely to fare badly in case of prolonged drought. Another serious type of injury, especially to newly planted trees, is sunscald on the exposed sides of the trunks. Probably the best means of prevention is to head the trees low enough to provide for shading by the tops.

It is said[1] that at the altitude of 2200 feet in West Virginia, snow and ice frequently cause much injury to young trees. It is a notable characteristic of the species for young trees to retain their leaves during much of the winter. Unless these are removed soon after turning brown, they are apt to become heavily weighted with wet snow and to cause severe breakage. Hail and spring freezes also cause much damage in that locality. The last, however, is not peculiar to high altitude alone as frost injury is frequent at much lower elevations. It was generally in evidence in central Maryland during the springs of 1945 and 1946 as has already been mentioned. This type of injury is easily overlooked, but the cambium will be found dark if a cut is made through the outer bark. Recovery usually takes place rapidly if the injured trees are left undisturbed, but healing will be slow if they are dug up for transplanting or the tops are severely cut back in preparation of the stock for grafting.

[Footnote 1: Verbal statement by Mr. Authur Gold, of Cowen, W. Va., made during April, 1946.]

Bearing Ages

Young trees may bear a few nuts three or four years after being transplanted, but it usually takes from 10 to 12 years for tops to become large enough to produce profitable crops. While there are occasional trees that become profitable at these ages, there are many that do not. The only significant record of yields yet made public is one reported by Hemming.[2] His statement shows that 18 seedling trees planted in 1930 bore an average of 29.5 pound (green weight) during six of the eight years from 1937 to 1944, inclusive, when crops were large enough to be separately recorded for each tree. The range in total production per tree for the six years was from 106 to 277 pounds. At an arbitrary price of 25 cents a pound, the average gross return per tree would have been $7.39 for each of the six crops. The 1944 crop was a practical failure. That of 1946, amounted to about 1000 pounds, or an average of about 55 pounds per tree.

[Footnote 2: E. Sam Hemming, Easton, Md., "Chinese Chestnuts in Maryland," Ann. Rep't., Nor. Nut Growers Association, Incorporated, vol. 35, pp. 32-34. 1944.]

The Seedling Tree

The original planting stock of the Chinese chestnut as grown in the United States consisted wholly of seed nuts imported direct from the Orient. It was therefore, inevitable that a period of seedling development should follow. The great majority of the earliest trees grown proved unfit for use as potential varieties, although with some exceptions, they produced nuts that were sweet and palatable. Since the middle 'thirties, superior strains have been introduced, cultural and environmental requirements have become better understood, and the outlook for commercial orchards is much improved.

To a great extent the seedling has served as well as would a grafted tree for the pioneer experimental work that had to be done. It has been far better than no tree at all and even now it has its advantages. With it there is no expense for grafting, no problems of congeniality between stock and scion and those of cross pollination are held at a minimum. Moreover, it must not be forgotten that it is only from seedling trees that superior varieties are possible. In 1946, the year in which this paper is being written, very few grafted trees are available from any source.

The Grafted Tree

The first varietal selections were made in 1930. Quite unavoidably they were chosen solely by what could be judged from the nuts with no knowledge of the bearing habits of the parent trees. These were first grafted in 1932 and first catalogued in 1935. Already by 1946, some had been supplanted by others of greater promise. Few grafted trees have been brought into bearing and with minor exceptions, it has not been possible to obtain bearing records. It is, however, mainly with the grafted tree that the future of the industry is expected to be built up.

Individual Varieties—Abundance

This variety was first catalogued in 1941 by Carroll D. Bush, then a nurseryman at Eagle Creek, Oregon. Of the very few trees of this variety sold by him, one went to Mr. Fayette Etter, Lemasters, Penna., with whom it early became a favorite among 7 or 8 he had under test. During 1945, he sent a quantity of Abundance chestnuts to Dr. J. Russell Smith, Swarthmore, Penna., who in turn forwarded 12 specimens to the Plant Industry Station. These arrived October 11 and were immediately placed in a refrigerator. On October 22, they averaged 50 to the pound and ranged from 38 to 76. The appearance was very attractive as the color was a rich brown and there was very little down over the surface. The cleaning quality was also very good and the flavor excellent.

The Abundance has attracted considerable attention and, while it does not appear to be listed in any nursery catalogue, a number of leading growers are using it in top working seedling trees and it may soon be available through regular nursery channels.

Carr

The Carr chestnut originated as one of two seedlings sent by the Department of Agriculture in 1915 to the late R. D. Carr, Magnolia, N. C. Sixty-two nuts from Mr. Carr were received by the Department in 1930. These were not especially attractive as the surface was thickly coated with gray down. The lot averaged 58 per pound and the nuts were considered large. Cleaning quality was very good and the flavor was sweet and pleasing. The variety was immediately named in honor of Mr. Carr although propagation did not begin until 1932. It is believed to have been the first variety of the species ever grafted in this country. The work was performed by H. F. Stoke, Roanoke, Va. Later the Carr became available for several years from a number of nurseries. It was a strong grower but often failed to make good unions with its stock and is not now in general favor.

Hobson

This also originated as one of two seedling trees sent to a private grower by the Department. He was Mr. James Hobson, Jasper, Ga., in whose honor it was named in 1930. It was later taken up by commercial nurserymen and widely distributed for several years. It has much in its favor as it is easy to graft, precocious, prolific, annual in bearing, and the nuts are very sweet. Also, the cleaning quality is very good, but the nuts are too small to meet market requirements of this country to best advantage. Furthermore, being small, they are expensive and time consuming of labor at time of harvest. The average per pound for a lot of 110 nuts received in 1930 was 78. Others received during later years were even smaller. The variety rapidly lost favor with most nurserymen and its propagation was largely if not entirely discontinued. However, for home use, it is much to good to be abandoned at this time.

Reliable

Reliable was an introduction of H. F. Stoke, Roanoke, Va., by whom it was propagated for a short time only, beginning in 1938. It is not known to have been catalogued by any other nurseryman. Ten fresh nuts in 1939 averaged at the rate of 79 to the pound. Six days later, after further curing had taken place, the number became 101 to the pound. Aside from having a good bearing record, there appears to be little reason for continuing this variety.

Stoke

This variety appears to be the result of a natural Chinese-Japanese cross. The original tree was grown by H. F. Stoke, Roanoke, Va., whose attention was attracted to it because of its habit of maturing early. He reports that in southwestern Virginia, burs often begin opening during the third week of August. In appearance, the nuts greatly resemble pure Japanese. The parent tree bears well but the nuts are lacking in good quality. Insofar as known propagation has been discontinued.

Yankee (Syn. Connecticut Yankee)

The Yankee originated as a chance seedling on property of E. E. Hunt, Riverside, Conn. It was first propagated by Dr. J. Russell Smith, Swarthmore, Penna., in northern Virginia by whom it was first catalogued in 1935. The writer has seen no specimens but according to Dr. Smith, the size and other features are very good. The parent tree is said to bear well and to be hardy where it is located, which is not far from Long Island Sound in the extreme southwestern corner of Connecticut.

Zimmerman

This originated as a 1930 selection made by the late Dr. G. A. Zimmerman, Linglestown, Penna. Very few sound nuts of Zimmerman have ever been produced, for soon after the first crop the identity of the tree became lost and eventually it was destroyed together with others in an overgrown nursery row where it stood. In one known case where there are grafted trees of bearing age, the nuts are regularly destroyed by weevils. Such nuts as have been seen by the writer have been of a dull brown color and have had surface down only about the apex.

The Zimmerman was first catalogued in 1938-39 by Dr. Smith. It is probable that as many trees of this variety have been sold and planted as of any one variety but performance records are difficult to obtain.

Potential Varieties

Other varietal selection are being made, mainly by the Bureau of Plant Industry, Soils, and Agricultural Engineering from trees at its various field stations. Some of these are already under test as grafted stock in various parts of the country. The most promising will be released to commercial nurserymen as soon as their superiority over existing varieties is established.

Pollination

There is much evidence that chestnut pollen is largely carried by insects although this has not been fully established. The Chinese chestnut is largely, although apparently not wholly, self sterile; more than a single seedling or grafted variety should be included in any planting. Several seedlings or several varieties would be better. In seedling plantings, all trees that produce inferior nuts should be removed in order to avoid danger of undesirable pollen influence, either on nut characters, or on the genetic makeup of the embryos if the nuts are to be used as seed.

Harvesting and Curing

Chestnuts should be harvested daily as soon as some begin to ripen and drop to the ground. They should be placed at once on shelves or in curing containers with wooden or metal bottoms through which the larvae of any weevils with which the nuts may be infested cannot penetrate and reach the ground. In areas of infestation, these grubs soon begin to bore their way out of the nuts and leave conspicuous holes in the shells. All infested nuts should be promptly burned.

In order to cure chestnuts to best advantage, they should be spread thinly on floors, or on shelves, or in shallow containers as just described, and held in a well-ventilated room. They should be stirred frequently and held for from 5 to 10 days depending both upon the condition of the nuts and the atmospheric conditions at the time of harvest: During the period of curing, the nuts will shrink rapidly in weight and the color will change materially. Both luster and brightness will largely disappear and, although still attractive, the nuts will quickly become dull brown. Three weeks is about as long as Chinese chestnuts usually remain edible without special treatment.

Chestnuts should be marketed as promptly as possible both to minimize deterioration and to take advantage of good prices which are usually highest early in the season.

Storing

Chestnuts in sound condition when stored may be kept fit for eating or planting for several months by any one of several methods. When available, cold storage with temperatures somewhat above freezing is the simplest and generally the most satisfactory method. Stratifying method. Stratifying in a wire-mesh container buried deeply in moist but well-drained sand is very satisfactory and successful. Another method is to hold the nuts in a tightly closed tin container either in a refrigerator or in cold storage at 32 deg. F. Burying under a porch or in the shade of a house or even in a bin of grain, preferably wheat or rye, is also a good method. Regardless, however, of temperature or other conditions, germination is likely to begin in early March and nuts intended for planting should be hastened into the ground as promptly as possible after that time.

Insect Pests

The two chestnut weevils are the principal insects attacking the nuts. These are exceedingly well-known in certain large areas where the chestnut is grown and in these areas both are often extremely abundant. Unless checked in some way they often render whole crops unfit for use. One of most effective means of control is to plant trees only in well populated poultry yards; however, in large developments, this is impracticable and other methods must be employed. In preliminary work carried on by the Bureau of Entomology and Plant Quarantine at Beltsville, DDT has given very encouraging results in the control of the weevil. The weevils have sometimes been called curculios, under which name they were well discussed by Brooks and Cotton.[3] The Japanese Beetle is also a serious pest as chestnut leaves are among its favorite foods. Control methods have been given by Hadley.[4] Another insect pest which feeds on the leaves is the June bug or May beetle. It works mainly at night and feeds on the newest leaves. It is seldom seen and usually disappears about the time when the operator becomes aware of its presence.

[Footnote 3: Fred B. Brooks and Richard T. Cotton, "Chestnut Curculios." U. S. Dept. Agr. Tech. Bul. 180. 1929.]

[Footnote 4: C. H. Hadley, "The Japanese Beetle and its Control." U. S. Dept. Agr. Farmers' Bul. 1856. 1940.]

Diseases

Blight is the disease attacking the chestnut tree with which the public is most familiar. The Chinese chestnut is strongly resistant although not immune as few old trees entirely escape attack in areas where blight is prevalent. In most cases healthy vigorous trees of this species overcome the disease within a few years after being attacked. The ones that die are usually those that have been devitalized in some way. The nuts are subject to attack by any of several diseases either before or after the harvest. A preliminary report on these has been made by Gravatt and Fowler.[5]

[Footnote 5: G. F. Gravatt and Marvin Fowler. Nor. Nut Growers Ass'n. Proc. 31: 110-113. 1940.]

Present Extent of Planting

With few exceptions the known plantings consist of small numbers of trees about residences. Occasionally there are one or two hundred trees in orchard arrangement. Production is not large and in most cases all sound nuts are either consumed locally or used by nurserymen and others for planting. The quantity that has reached the wholesale market is known to be small although a beginning in that field has been made.

Future Outlook

Extensive expansion has not appeared possible in the near future until the 1946 crop was harvested. This was unexpectedly large and a number of tons are known either to have been planted immediately or set aside for planting in the spring of 1947. It is conceivable that annual production of nuts available for seed purposes will increase rapidly. In this case, the extent of planting within the next few years will be entirely a matter of guesswork.

Extensive planting in the early future cannot be considered economically safe for in addition to the usual number of problems that must be solved in establishing any new horticultural enterprise, chestnut growers must expect keen competition with imports from both Europe and Asia. At the outbreak of World War II, an average of more than 16 million pounds of chestnuts were yearly being imported into this country.[6] These imports will doubtless again appear with the return of normal international relations.

[Footnote 6: Computed from Table 541, p. 413, Agricultural Statistics 1938. U. S. Dept. Agr. 19]

Furthermore almost an exact half-century ago, the chestnut outlook was regarded as being so bright that it could hardly go wrong. During the middle and late 'nineties extensive chestnut developments were established in certain eastern districts mainly by use of Paragon and other varieties of European parentage. Thousands of small plantings were developed about home grounds and occasionally there were large orchards. The greatest developments were conducted by top working suckers that sprung up from stumps of native chestnut trees on cutover mountain land. Hundreds of acres were handled in this manner. Without exception, all ended in financial disaster.

Summary

The nut of the Chinese chestnut is an excellent product. It is unexcelled in sweetness and general palatability by any other known chestnut. The tree bears well and is about equally as hardy as the peach. It appears to require much the same conditions of cultural environment as does that fruit. It is practically the only species of chestnut now being planted by informed growers in the eastern part of the United States.

It is thus far grown in this country almost entirely as seedling trees. Variation is about what was to be expected, with the majority of bearing trees proving to be poor producers and, in most cases, with nuts too small to sell well.

Varietal selections of much promise are being made; the first appeared in 1930 and were first catalogued in 1935. Some of the earliest have already been dropped as their defects came to be known, and others of greater apparent promise have originated. The process of selection is constantly going on and further introductions should shortly appear.

By taking certain simple steps chestnuts in sound condition may be kept in usable condition for many weeks.

The Chinese chestnut is subject to attack by certain serious natural enemies. These include both insects and diseases and the tree as well as the nuts are affected. However, all that are now known appear controllable.

Past planting has been largely limited to small numbers of trees mainly about residence grounds. The total number of trees available for planting has never been large, due chiefly to the scarcity of seed nuts needed for nursery use. Production, however, rose sharply with the harvest of the 1946 crop which was unexpectedly large. Annual production may continue to increase since the number of trees of bearing age is likely to become appreciably greater each year. Nursery planting is likely to be proportionately greater. The extent of future planting will doubtless be correspondingly influenced.

Present enthusiasm over the Chinese chestnut is very great and it is possible extensive planting may soon take place. It is believed, however, that this would be unwise from an economic point of view. There are many uncertainties in connection with the industry in its present state of development, and, not improbably there will be keen competition in the market with imported chestnuts from both Europe and Asia as soon as international relations become normal.

Bearing Record of the Hemming Chinese Chestnut Orchard

By E. Sam Hemming, Easton, Maryland

Our Chinese chestnut trees have aroused such interest that we are sure the readers of the Proceedings will wish to hear of the large crop harvested in 1946. A year ago an unseasonal spring brought a frost that killed back the six inches of soft new growth. As a result, the 1945 crop amounted to less than 250 pounds. This year the 18 trees produced 1138 pounds, 938 by actual weighing and 200 estimated. This is an average of 63 pounds per tree, with the largest crop of 124 pounds on No. 19, and the smallest on No. 14 of 22 pounds.

These trees are now 18 years old and were unfortunately planted too close. But using a spacing of 30 feet x 30 feet, they would have borne 3000 pounds per acre and if planted 40 feet x 40 feet would have borne 1600 pounds per acre. Figure this crop at 25c a pound and you would get a really high return. This year the price was much better than that, but we planted the crop.

The tree record was as follows: Number 1—38; Number 2—25; Number 3—30; Number 4—52; Number 5—44; Number 6—30; Number 7—42; Number 8—40; Number 9—45; Number 10—58; Number 11—56; Number 12—48; Number 13—58; Number 14—22; Number 15—50; Number 16—80; Number 18—86; Number 19—124; Total of 938 + 200 (estimated) = 1138.

It is also worthy of note, that No. 19 is spaced 30 feet from No. 18 and No. 16 is the same distance from No. 18, while all the other trees are spaced 16 feet apart. An acre of trees like No's. 16, 18 and 19, spaced 30 feet apart, would average 96 pounds per tree or 4200 pounds per acre, a really tremendous crop.

We had one disappointment this year, in that our method of controlling the weevil was not completely effective. To our chagrin we found that, while we were diligently picking the nuts up each day, some of the larvae were escaping through the cotton bags to reinfest the ground. Next year, we will use metal containers and we are sure that will stop them. We will fumigate if necessary. We do not particularly fear the weevil as we are sure that spraying, and fumigation will clean them up; after that proper harvesting should control them. We have heard that the U. S. D. A. has found the use of DDT to be effective. In another county a raiser of hybrid corn seed dusted his corn with DDT by plane, to kill the Japanese beetle, for $3.00 per acre. Surely that method would be adaptable to chestnut orchards to control the weevil.

At the present time we are using our entire crop for seed purposes and this year we sowed 40 to 50 thousand nuts. We carefully grade the seed, not only discarding any infested nuts, but all moldy, split or undersized nuts, so that we get trees grown only from the choicest. By doing this we feel that although the trees are seedling raised, they come from parent trees that are bearing well, and from which all extraneous pollen is excluded so that the customer has a good chance of getting a tree that will bear well.

The seed is sown in the fall, because it keeps better that way and germinates better too, although we have some trouble from a mole-mice combination. The seeds are sown in shallow trenches 6 inches apart and 2 inches deep and back—filled either with sawdust or light soil. On top is mounded a further 4 to 6 inches of soil which is removed in the spring. This reduces damage from freezing and thawing.

We do not doubt for a moment that the Chinese chestnut is here to stay as an important food crop for the United States.

Walnut Notes

G. H. Corsan, Islington, Ontario

I find the Ohio, Ten Eyck, Stabler, Allen and Wiard black walnuts inferior and unsuitable. The Stabler has only a small crop every five years. Very excellent varieties, I find, come from Thomas seedlings.

The black walnut makes an excellent stock for the Persian walnut in low and slightly damp ground. I bud the Persian on the black during August.

The Japanese heartnut and the butternut x heartnut hybrid can be grafted on black walnut. The Persian walnut when grafted on the black decidedly outgrows the latter. The reverse is the case when Japanese heartnut, Japanese butternut, or hybrids of either are grafted on the black.

So far I have not found one good butternut worthy of naming, but there is one Japanese butternut that grows in clusters of 17 or even more that has a very thin shell; it is the Helmick. I have, however, very many named as well as unnamed black walnut seedlings that are very excellent nuts.

This has been a very cold summer and I cannot state yet as to the maturing of the larger black walnuts, as they require a long season to mature properly. Pecan and hican trees grow well at Echo Valley and the small twigs harden up so that there is never any winter killing but the nuts do not fill well; in consequence I am using the trees as stocks for grafting with good shagbarks. The Weiker hickory ripens nicely with me and I consider it one of the best varieties in every way.

Self-fruitfulness in the Winkler Hazel

By Dr. A. S. Colby University of Illinois, Urbana, Illinois

To insure fruitfulness in nut plants it is generally recommended that more than one variety of each kind be planted in reasonably close proximity to help in bringing about cross-pollination. Then, with other conditions being favorable, the grower would be more certain of good yields of well-filled nuts.

With specific reference to the filbert, the literature contains references to the effect that provision for cross-pollination is essential. However, one exception is listed. In the report of the proceedings of the 26th (1935) annual meeting of the Northern Nut Growers' Association, D. C. Snyder of Iowa says on page 47, "The catkins of Winkler always come through the winter bright and the variety can be depended upon to bear without other varieties near for cross-pollination."

The writer has been interested in this subject for several years. The question arises; how near were Mr. Snyder's Winklers to other varieties and in what direction with reference to the prevailing winds? It is not known just how far filbert pollen may be carried and still function. A planting of Winkler filberts consisting of about 30 bushes was set on the University Farm at Urbana in 1940. Crops have been borne annually since that time. The planting was isolated from other filberts to the southwest by about one-fourth of a mile.

In an effort to determine whether the variety was self-fruitful, plants were dug in the early winter of 1943 after the rest period was over and reset in the greenhouse. The plants leaved out in January, 1944, and both male and female flowers appeared soon after. The pollen was applied to the pistils both by shaking the branches and by means of a camels hair brush. Nearly all the blossoms set and the nuts carried through to maturity. The experiment was repeated in 1944-45 with the same results.

It is therefore concluded that the Winkler filbert is self-fruitful and may safely be planted alone where climatic conditions are favorable for filbert production.

Hickories and Other Nuts in Northwestern Illinois

By A. B. Anthony, Sterling, Illinois

I have something like 25 grafted hickories of my No. 1 (Anthony) variety. The largest tree now has a trunk of 5-1/2 inches in diameter; has 20 nuts on it this year; and while it has had but few nuts each year, has missed bearing but one season in the past seven years. Other No. 1 trees run from 3-1/2 inches, in diameter down to about 1 inch. One 3-1/2 inch tree is offering its second bearing with five nuts this season. All these trees were grafted in cutover woodland tracts and moved here except the largest one which was moved in 1930 and grafted in 1933, 30 inches high and never trimmed for a higher head. Heavy annual catkin bloomer, few pistillates so far.

Of my No. 2 variety, one tree transplanted in 1927 now has something like 25 nuts on it. The No. 3 hickories, five of them, have never borne either pistillate or staminate blooms. No. 4 is a hican from the parent tree of which I have had but three good nuts. The weevil moth works so well in dense woods that rarely are the nuts good there. The nuts are attractive and should not discolor like the lighter hickories, should their opening husks get rained upon when maturing.

Men of the future must decide on the merits of these trees. Of the two Hagen trees grafted in 1931, one now has its first nuts, eight in number. I have been told that some one will cut these trees down some day. One of our county or state officials said a short time back that "if hog troubles keep coming on as of late, in 50 years we will not be able to raise hogs." With corn being the main hog food and the corn borer coming, this may come to be quite true, and then perhaps more men will get new vision as to where their meat is coming from.

The past three years have offered almost no hickories at all. Hickories do not like shade, but they have to grow where the squirrels have planted them. Carrying a nut 100 yards to bury it would doubtless be about a squirrel's limit. I have noticed in timber of sizeable growth a north slope showed no young hickories, while a south slope showed a scattering few. Oak trees in this section predominate when it comes to groves of one species. Cottonwood trees come up here and there, probably because their seed is wind-carried. Willow sticks get carried down stream and get lodged, and grow. I have known a few young oaks to come up on my place all of a mile and a half of such woods. How come? It is probably the combination of the blue jay and squirrel, this time. No trouble for the blue jay to travel some distance and put his acorn in a bark crevice of cottonwood or willow tree. Along comes a wandering squirrel, finds the acorn, and if not hungry enough puts in the ground where it has a chance to grow. I have seen blue jays start off with chestnuts and the nearest trees they could reach were willows one-fourth mile or further away.

For some reason there seems to be a tendency for the hickories to bear in seasons when the black walnut does not and the walnut to bear when the hickory fails. Last year, except for filling, walnuts did reasonably well and this year, at least with my Rohwer variety, the yield is still better except that the nuts are unusually small, doubtless because all of July and up to the 9th of August it was very dry.

Throughout my years there have always been walnut trees on the place, first started by a pioneer land owner, then squirrels took it up, so I have a choice of stocks I did not have in hickories.

Two of my Rohwer trees have trunks 12 inches in diameter; one is 11 inches and the other 14 inches in diameter. For years these trees, grafted in 1931, have been very profuse with catkins, but with few nuts. I have heard other complaints of it not bearing.

My complaint with all walnuts grown in Northwest Illinois is that so many kernels turn out black and immature. I am inclined to blame it, in part, to the walnut shuck, which takes in so much moisture. The hickory shuck is much dryer and never has so many immature kernels. Late summer is generally the dryer part of our growing season, which can well be the cause. In the year 1940, we had an excess of moisture in that it rained day after day all through August, and that is the only season I can say we had good walnuts with practically all good, light-colored kernels.

I have a few Thomas walnuts planted on the edges of the lowest flat ground I possess, hoping that they may there get more moisture and produce completely matured nuts.

We had on August 9th about one inch of rain and since that 2-1/2 inches more. So far, throughout this month, I have been carrying about 15 gallons of water daily to two Rohwer trees and hope for some better filled walnuts, though they are unusually small. I am writing this August 24th.

Nut Trees for Ohio Pastures

By Dr. Oliver D. Diller, Wooster, Ohio

Today I would like to discuss for a few minutes the possibilities of nut trees for shade and nut production in permanent pastures on Ohio farms.

One of the most important developments in Ohio agriculture during the past decade has been improvement of pasture land through fertilization, new varieties, and combinations of grasses and clovers, and better methods of management. As one drives over the State it is evident that many farmers practice "clean" agriculture which means clean fence rows and treeless fields. Shade on a hot summer day is an important item to contented cows, so today I am going to plead the case for a cow out on pasture on a sweltering day. I believe that nut trees, particularly black walnuts, can be of real service in the fence rows and the interior of hundreds of permanent pastures in Ohio.

In 1939, L. R. Neel,[7] of the Tennessee Agricultural Experiment Station, published an interesting article on the effect of shade on pasture. The results indicated distinct improvement in the carrying capacity of the pastures which had black locust and black walnuts spaced regularly throughout the fields. Improvement was evident both in the amount of Kentucky bluegrass and the pounds of beef produced. So far as I know, no evaluation has ever been made of the direct effect of shade on the contentment and consequent increase in efficiency of cattle for either beef or milk production. I believe this is an important factor and is frequently used as an excuse for woodland grazing.

[Footnote 7: Neel, L. R., 1939. The effect of shade on pasture. Tenn. Agr. Exp. Sta. Cir. 65.]

Another study similar to the one in Tennessee was conducted by R. M. Smith in southeastern Ohio during the period 1939 to 1941.[8] Dr. Smith made an intensive study of the effects of black locust and black walnuts upon ground covers and he found that in poor pastures black walnut trees improved both the species composition and chemical content of the plants growing under the trees. He rated walnut high as an ideal pasture tree because of its period of leaf activity; its light crown canopy; its small, fragile leaves which decompose rapidly, and are high in mineral matter and nitrogen; its deep tap root which competes very little with the surface rooted grasses for moisture and nutrients; its hardiness; and finally its high commercial value.

[Footnote 8: Smith, R. M., 1942. Some effects of black locust and black walnut on southeastern Ohio pastures. Soil Science, Vol. 53, No. 5.]

It seems apparent, therefore, that the introduction of improved black walnut trees into permanent pastures would be practical from the agronomic angle to say nothing about the beneficial effect of shade to livestock and possible income from occasional crops of high quality nuts.

One stumbling block to the adoption of this idea is the protection of the trees during the period of their establishment. The conventional cattle guard with three or four long posts supporting a wire fence is expensive in both labor and materials.

During the spring of 1946 in connection with my forestry instruction at Ohio State University, I had as one class project the planting of 50 black walnut seedlings of selected parentage in the cattle and poultry ranges on the University farm. Thirty of these trees were planted along a fence row at 32 foot intervals and were protected by a single electric wire connected to a battery charger.

The set-up is illustrated in figure 1 which shows the charger at one end of the line and the wire supported by the line posts and a short single post opposite each tree. The one year old seedlings were planted 4 feet from the fence at alternate posts and the wire zig-zagged along the line to create the guards around the trees. Within a few days after planting and completion of the electric guards the trees were mulched to control weeds and conserve soil moisture.

While this experiment has been in effect for only one growing season, the results, to date, indicate that this method is effective in providing protection from livestock. Growth and survival of the trees has been very satisfactory thus far.

The advantages of this method appear to be the rather low cost of labor and materials and ease of installation.

Within the next decade, we should be able to determine how the nuts from these seedling trees compare with the parent tree and there should be adequate shade for all classes of livestock on either side of the fence.

How Hardy Are Oriental Chestnuts and Hybrids?

By Russell B. Clapper and G. F. Gravatt Plant Industry Station, Beltsville, Maryland

One of the questions most frequently asked in regard to the Oriental chestnuts is, will they thrive in a given locality? Broadly speaking, with respect to temperature requirements these chestnuts have been found about equally hardy with the peach. Some strains of the Chinese chestnut appear to be superior to the Japanese chestnut in hardiness.

The Chinese chestnut is more widely planted in this country than the Japanese chestnut and more information has been collected on the hardiness of the former species than of the latter. The Chinese chestnut is growing satisfactorily in certain plantings as far south as Orlando, Fla. and the other Gulf States, northward to the southern tip of Maine, and westward as far as Iowa. But many areas within this large zone are unsuitable for growing Chinese chestnuts because of more severe climatic conditions.

Specific data have been obtained relating to several types of winter injury of Oriental chestnuts and hybrids. This information is limited to the performance of mostly young trees and to a comparatively small number of locations.

The fall freeze that occurred in mid-November, 1940, was studied in detail by Bowen S. Crandall,[9] formerly of this Division. Widespread damage occurred to Oriental chestnuts in the central parts of South Carolina, Georgia, and Alabama. Temperatures before the freeze had been mild, and heavy rains in early November had broken a drought. On the nights of November 15 and 16, temperatures of 12 deg. and 14 deg. F. were reported by various farmers, and a drop to 20 deg. F. was general on the night of the 16th. The damage to chestnuts by this freeze was increased because of the mild temperatures and heavy rains that preceded the freeze. The chestnut trees were not able to attain complete dormancy. Those trees, however, that were growing on uplands or on sites that were well air-drained suffered much less damage. Apparently equal damage was inflicted to Chinese and Japanese chestnuts.

[Footnote 9: Crandall, Bowen S. Freezing injury to Asiatic chestnut trees in the South in November, 1940. Plant Disease Reporter 27:392-394. October 1, 1943.]

On one farm near Columbus, Ga., four plantings were located at different elevations. The planting at the lowest elevation, maintained as a well cultivated orchard, suffered almost 100 per cent loss from this fall freeze. The trees at the highest elevation, in a forest planting, were practically uninjured. The damage from this freeze varied from killing of buds and shoots to killing of complete trees. Many owners of chestnut plantings did not notice the damage until the following spring. Fortunately fall freezes of this magnitude occur only infrequently.

In the winter of 1944, this Division lost 23 per cent of its hybrids at Glenn Dale, Md., from freezing following abnormally high temperatures. The hybrids had been fertilized in October of the preceding year, but the effect on the extent of freezing damage is not known. The months of November, 1943, through March, 1944, were characterized by extremely variable temperatures. For example, in November a minimum of 15 deg. F. occurred on the 17th, a maximum of 72 deg. on the 19th; in December a maximum of 66 deg. on the 3rd, a minimum of 2 deg. on the 16th; in January a minimum of 8 deg. on the 17th, a maximum of 74 deg. on the 27th; in February a minimum of 11 deg. on the 2nd, a maximum of 72 deg. on the 25th; in March a minimum of 8 deg. on the 10th, a maximum of 81 deg. on the 16th.

The extremes of temperatures in any one of these months may have been sufficient to cause damage to chestnut, although the extent of damage is influenced by the physiological conditions within the tree. The usual type of injury to the hybrids was a killing of the cambial cells extending from the base of the trunk up to varying heights. The cambial region was grayish-black and the inner bark was sappy and greenish-brown. More trees were injured and killed on the lower portions of the plot than on the higher portions.

This catastrophe afforded opportunity to study resistance of the hybrids to freezing. In the lower part of the plot there were several 3-year-old American chestnut seedlings that were not damaged. Sixteen per cent of first generation hybrids of Chinese and American chestnut were killed. Chinese by American backcrossed with Chinese were killed to the extent of 36 per cent. Chinese by Japanese chestnut of the second generation were killed to the extent of 35 per cent.

Despite this extensive killing of hybrids by extreme variations of winter temperatures, older Chinese and Japanese chestnuts on slightly higher ground in the same plot suffered no visible injury. These old trees have rough bark, which may serve as an effective insulator against extremes of temperature. In 1944, there was no damaging late spring frost, and these old trees produced the largest nut crop in their history.

Winter temperatures of -25 deg. F. or lower are usually injurious to Oriental chestnuts. A few reports of chestnuts surviving temperatures of -25 deg. F. have been recorded, but usually Oriental chestnuts do not thrive in those northern States or regions where such temperatures occur.

Many of our cooperators report that late spring frosts frequently cause failure of chestnut crops. Damaging frosts in late spring occur more frequently and over greater areas than early fall frosts or extreme winter temperature variations. A late spring frost in 1945 reduced the chestnut crop at Glenn Dale, Md., from 50 bushels expected to 3 bushels actual. A freeze of 24 deg.F. on the nights of April 4 and 5 was sufficient to inflict this damage after two weeks of abnormally warm weather. Many of the trees were visibly injured, with wilted or dried unfolding buds. Other trees on higher ground were not visibly affected, yet they produced no crops.

Again it was noted that the American chestnut, followed by American chestnut hybrids, sustained none to little damage. The American chestnut, besides its inherent resistance to freezing, leafs late in the spring. Most of the crop of nuts obtained in 1945 was produced by the American chestnut hybrids.

Late spring frosts in 1945 were very extensive, reaching throughout the eastern and northeastern States, and there were practically no chestnut crops. There were also numerous reports of late spring frost injury to chestnut in the Central States.

In order to reduce freezing injury to Oriental chestnuts, it is essential that they be grown on sites that have excellent cold air drainage. As an approximate rule, these chestnuts should be planted on sites similar to those that are best for peaches. The orchard planting is not the only type that is subject to winter injury; forest plantings, ornamental plantings, and plantings for wildlife are also subject to winter injury especially if they are not on the most favorable sites.

Growing Chestnuts for Timber

By Jesse D. Diller Plant Industry Station, Beltsville, Maryland

Before the turn of the century, and even before chestnut blight had swept through our eastern forests, destroying one of our most valuable commercial timber trees, European and Asiatic chestnuts had been introduced. They made variable growth in the Gulf States, along the eastern seaboard from Florida to southern Maine, the southern half of Pennsylvania, southwestern Michigan, southeastern Iowa, down the Mississippi River Valley and on the Pacific Coast. These trees were grown for horticultural purposes, and for the most part, represented large-fruited varieties of Japanese chestnuts. They were not regarded as having forest-tree possibilities for in the open situations in which they were usually planted to insure early fruiting, the trees developed low-spreading crowns, resembling orchard trees. However, after the blight became fully established and it became apparent that our American chestnut was doomed, and that these scattered Asiatic chestnut trees had a natural resistance to this disease, a new interest developed in the Asiatic chestnuts as a possible substitute for the American chestnut.

The interest in and need for resistant, forest-type chestnuts became so great that the U. S. Department of Agriculture imported from the Orient seed of strains that might be suitable for the production of timber, poles and posts, with tannin and nuts as valuable by-products—qualities inherent in our native chestnut. The Division of Forest Pathology, Bureau of Plant Industry, Soils, and Agricultural Engineering has been carrying on the project of testing Asiatic chestnuts as timber trees. Professor R. Kent Beattie of this Division was in China, Korea, and Japan from 1927 to 1930, and collected over 250 bushels of seed for shipment to this Division. The seeds represented four species: Castanea mollissima—the Chinese chestnut; C. henryi—the Henry chinkapin; C. seguinii—the Seguin chestnut; and C. crenata—the Japanese chestnut.

Direct Seeding Studies

At the very beginning of these investigations in growing Asiatic chestnuts as timber trees, it was believed that greater success in establishment could be obtained by planting seedlings, rather than by direct seeding. In direct seeding trials during the early thirties the planted nuts were promptly devoured by rodents. Sixteen years of field experience has proven the soundness of this belief. The imported nuts were planted in the Division's nursery at Glenn Dale, Md., and the resulting seedlings distributed as 1- and 2-year-old trees to cooperators throughout the eastern United States.

In order to thoroughly test the possibilities of direct seeding as an economical method of establishment, this Division during seven years (1939 to 1942, and 1944 to 1946) planted over 7,000 nuts by direct seeding in 200 locations in 18 eastern States. It was suspected that the greatest hazard to direct seeding in or near forests would be rodents. Accordingly, in the spring of 1939 and 1940, 400 nuts and 600 nuts, respectively, were coated with a strychnine-alkaloid rodent repellent, and a comparable number of seeds, for both years, were left untreated to serve as checks. The checks were held in sphagnum moss at Beltsville, Md., and the nuts to be treated were packed in sphagnum moss and expressed to Denver for treatment by the Division of Wildlife Research, the Fish and Wildlife Service, Department of the Interior. Only 5.9 and 2.5 per cent of the treated seeds developed into seedlings, whereas 22.6 and 13.5 per cent of the untreated seeds produced seedlings. Not only did more of the treated seeds fail to germinate than of the untreated seeds, but the seedlings from the treated nuts were less vigorous. Because of the results obtained, the rodent-repellent study was discontinued at the end of the second year.

In 1941 and 1942, over 4,000 untreated chestnut seeds, representing 22 strains, were planted in 12 locations in eight eastern States. The seed source was entirely from American-grown, Asiatic chestnut trees growing in 28 locations in 16 eastern States. They represented Chinese, Japanese, hybrids, and also a limited quantity of American chestnut seed. Seed of the American species was included primarily to determine whether or not it differs from the Asiatic species with reference to establishment by direct seeding. The results for the two years confirmed our earlier beliefs: Only 2.2 per cent in 1941, and 4.0 per cent in 1942, developed into seedlings, of which only a remnant have survived. No species or strain differences were apparent.

"Tin Can" Method

In 1944, the tin-can method was employed in planting 400 nuts in four eastern States. By this method 15.5 per cent of the planted nuts developed into seedlings, representing a fourfold increase over results obtained for the three previous years. One end of a No. 2 can is removed, and a cross is cut in the other end with a heavy-bladed knife. The open end of the can is then forced into the ground, over the planted nut, so that the top lies flush with the ground level. The four corners at the center of the cut top then are turned slightly upward, to allow a small opening through which the hypocotyl of the developing seedling can emerge. The can completely disintegrates by rusting within two or three years, and does not interfere with the seedling's development.

An examination made of the various burrows about the tin cans, and also of the teeth marks on fragments of chestnut seedcoats lying about, indicated that not only squirrels, but other rodents, such as chipmunks, field mice, moles, and even woodchucks were probably involved in the direct seeding failures.

In 1945 and 1946, the tin-can method was tested widely on farms, to determine its possibilities in securing establishment of blight-resistant chestnuts without a great outlay of cash to farmers. In 1945, five seeds were distributed to each of 90 cooperators residing in the Piedmont and southern Appalachian regions, and in the lower Mississippi and Ohio River valleys; and in 1946, to 38 cooperators residing in the Middle Atlantic States. Preliminary results indicate that 40.0 and 37.2 per cent of the nuts planted by the farmers developed into seedlings. It should be pointed out that these results are not strictly comparable with those of previous years, because most of the farmers preferred to plant the chestnuts in their gardens, and under these conditions the nuts were not exposed to the severe competition and the extreme rodent hazards that occur in the forests.

Further proof of the superiority of planting seedling stock over direct seeding as a method of establishment is indicated in the results of an experiment initiated in 1939. One hundred and fifty 1-year-old seedlings and 150 nuts, all of the same Chinese strain, were planted on cleared forest lands in the Coastal Plains, the Piedmont, and the southern Appalachian regions, and in the Middle West. At the end of the eighth year, at each location, establishment and development of those originating from the 1-year-old transplants were better than those originating from seed, and their average survival was six times greater.

Distribution of Planting Stock

During the period 1930 to 1946, the Division of Forest Pathology distributed thousands of Asiatic chestnut seedlings to Federal, State, and private agencies for experimental forest plantings in 32 eastern States. The ten States receiving the most planting stock, in the order named were: North Carolina, Tennessee, New York, Pennsylvania, West Virginia, Virginia, Ohio, Georgia, South Carolina, and Maryland. The purpose of this seedling distribution was to obtain information concerning the little-known characteristics of the Asiatic chestnuts—their soil and climatic requirements, and their range adaptability.

Selection of Planting Sites

At first the selection of the planting sites was left entirely to the judgment of the cooperators, and most of them assumed that the Asiatic chestnuts have site requirements similar to those of the native American chestnut. Because the American chestnut often occurs on dry ridges and upper slopes, especially where soil is thin and rock outcrops are frequent, the cooperators proceeded to plant the Asiatic chestnuts on similar "tough" sites. They believed that the planting of forest-tree species is justified only on defrosted areas that have reverted to grassland, or worn-out, unproductive agricultural land, or on wastelands—sites that we now know are better suited to the growing of conifers rather than hardwoods. As a result of this unfortunate choice of site selection, together with the several severe drought periods recurring in the early thirties, the cooperators lost most of their trees during the first and second years after planting.

Inspections of some of these planted areas after a lapse of from 10 to 15 years indicated that the sites still support only a scant herbaceous cover, with broomsedge and povertygrass predominating, and with no evidence of native woody species encroaching on the areas. The few surviving Asiatic chestnut seedlings were sickly looking, multi-stemmed, misshapen trees, heavily infected with twig blight and chestnut blight, and severely damaged by winter injury. But despite these heavy losses, a few plantations succeeded at least in part, and from these limited areas, together with an appraisal of the situations where some of the earlier planted chestnuts grew well, valuable information as to the site requirements of the Asiatic chestnut species was obtained.

Site Requirements

These field studies clearly showed that the site requirements of the Asiatic chestnuts, particularly with reference to soil moisture, are more nearly like these of yellow poplar, northern red oak, and white ash, than like the American chestnut or the native chinkapin species. On fertile, fresh soils that support the more mesophytic native species, Asiatic chestnuts remained relatively disease-free, developed straight boles, made satisfactory growth, and were able to maintain themselves in the stands in competition with the other rapid-growing associated hardwood species.

The indicator plants that suggest good sites for Asiatic chestnuts are: (a) Tree species—yellowpoplar, northern red oak, white ash, sugar maple, and yellow birch; (b) shrub species—spicebush; (c) herbaceous species—maiden hair fern, bloodroot, jack-in-the-pulpit, squirrelcorn and/or Dutchman's breeches. Plants that indicate sites too dry for forest-tree growth of Asiatic chestnuts are: (a) Tree species—the "hard" pines, black oak and scrub oak; (b) shrub species—dwarf sumac, and low blueberry; and (c) herbaceous species—broomsedge, wild strawberry, and povertygrass. Plants that indicate sites too wet are: (a) Tree species—black ash, red maple, and willows; (b) shrub species—alder; (c) herbaceous species—sedges and skunkcabbage.

Climatic Test Plots

On the basis of the experience gained from the earlier, extensive distribution of Asiatic chestnut planting stock, the Division of Forest Pathology, during the years of 1936, 1938, and 1939, established 21 Asiatic chestnut climatic test plots on cleared forest lands in eight eastern States on the most favorable sites obtainable. These plots, with their isolation borders, aggregating slightly less than 32 acres, and accommodating nearly 22,000 trees spaced 8 by 8 feet, occur from northern Massachusetts, along the Alleghenies southward to the southern Appalachians in southwestern North Carolina, and from the Atlantic seaboard, in southeastern South Carolina through the Middle West to southeastern Iowa. More than 20 strains are being tested at each place, including Chinese, Japanese, Seguin, and Henry species, as well as hybrids, and progeny of some of the oldest introduced chestnuts. Most of the plots are fenced against livestock and deer.

Although the results from these plots are as yet entirely preliminary, during the 8- to 11-year period of testing, valuable information has already been obtained: (1) The range of the Asiatic chestnuts tested does not coincide entirely with the range of the American chestnut or the native chinkapins. All Asiatic chestnut species that have been tested have failed at Orange, Massachusetts, where the American chestnut grew in abundance. In southeastern South Carolina, where the several species of native chinkapin thrive, some of them attaining a height of 20 feet, the Asiatic species have largely failed. On the other hand in northern Indiana and southeastern Iowa, entirely outside the botanical range of the American chestnut, a few Chinese strains have done remarkably well. (2) The Chinese chestnuts have a much wider range adaptability to site than the Japanese chestnuts; the latter are more restricted to mild climate and appear to require somewhat better site conditions. Of ten Chinese strains tested, only four can thus far be recommended for future planting in the Middle West. One Chinese strain that has thus far proven far superior to the others, in all the climatic plots, was introduced by the Department of Agriculture as seed from Nanking, China in 1924. (3) Poorly aerated soil is an important limiting factor in all regions where the chestnuts were tested.

Establishment by Underplanting and Girdling

On the basis of the field experience gained from the wide distribution of Asiatic chestnut planting stock and the information thus far obtained from the climatic test plots, a new method of establishing Asiatic chestnut under forest conditions was initiated in the spring of 1946, and is now being tried on a limited scale. It consists of underplanting, with chestnut seedlings, a fully stocked stand of hardwoods ranging from 4 to 8 inches in diameter breast height in which the predominant species are yellow poplar, northern red oak, white ash, and sugar maples. All overstory growth 5 feet and over in height is then girdled. As the girdled overstory trees die, they gradually yield the site to the planted chestnuts in transition that does not greatly disturb the ecological conditions, particularly of the forest floor. Rapid disintegration of the mantle of leafmold is prevented by the partial shading, which the dead or dying overstory, girdled trees cast. At the same time, the partial shading hinders the encroachment of the sprout hardwoods and the other plant invaders (which would normally become established if the planted area had been clear cut) until the chestnuts have become fully established. Not only does this system provide the best site conditions conducive to the development of forest-tree form in the Asiatic chestnuts, in limited areas, but also under establishment conditions that require a minimum amount of maintenance.

Summary

In general, Asiatic chestnuts, when grown for timber purposes, are best adapted to northern slopes, above frost pockets on cool protected sites, on deep, fertile soils having a covering of leaf litter and humus in the top soil, a soil that is permeable to both roots and water, and that has a good water-holding capacity. The plant association, above mentioned as indicating ideal sites for Asiatic chestnuts for best timber development, occur in rich soils of slight hollows in moist hilly woods and on the mountains in cove sites.

Improved Methods of Storing Chestnuts

By H. L. Crane and J. W. McKay Plant Industry Station, Beltsville, Maryland

Trees of the Chinese chestnut, Castanea mollissima, are quite resistant to the chestnut bark or blight disease. The heavy bearing of the trees together with the good quality of the nuts produced has stimulated planting of trees to replace those of the American species largely killed by that disease. Although a few horticultural varieties of Chinese chestnuts have been introduced and propagated, the great majority of the bearing trees are seedlings. In seedling plantings seldom do two trees produce nuts of the same size, color, and shape. All of these nuts when properly harvested, treated, and stored are sweet and edible and nourishing as food either raw, boiled, roasted, or combined with other foods in poultry dressing, salads, or pancakes. Then too, there is a big demand for Chinese chestnuts as seed for the purpose of growing seedling trees to be planted in orchards or to be used as rootstocks in propagating horticultural varieties. In either case, it is often desirable to store the nuts for several months before using them.

Chestnuts are not like the oily nuts, such as pecans, walnuts, almonds, filberts, or peanuts, that must be dried to a moisture content of 5 to 8 per cent to store well. Chestnuts are starchy nuts, containing about 50% moisture when first harvested, and on drying they become very hard. In experiments conducted at the U. S. Horticultural Field Station, Meridian, Miss., it was found that the loss in weight of chestnuts ranged from 16.2 to 30.5% when stored for 4 months in open containers at 32 deg.F., and 80% relative humidity. In an experiment in which chestnuts were stored 4-1/2 months at 32 deg.F., they lost 18.8% in weight when stored in burlap sacks, 3.7% when stored in waxed paper cartons with tight-fitting lids, and 2.0% when stored in friction-top cans. Furthermore, chestnuts on drying lose their viability and become worthless. Chestnuts lose moisture rapidly and become subject to spoilage due to molds and other fungi and therefore must be considered as highly perishable and handled accordingly.

There is a great difference in the keeping quality of the nuts produced by different trees in that some are very susceptible to infection by molds and bacteria and spoil quickly while others keep quite well. At Meridian, Miss., nuts from 5 different seedling trees ranged from 2 to 34% mold infection at harvest. Studies made by John R. Large at U. S. Pecan Field Station, Albany, Ga., showed that much of the infection of the nuts by molds occurred after they had fallen from the burs and while the nuts were in contact with the soil. It is, therefore, essential that the nuts be harvested promptly after they are mature.

As a general practice the nuts should be gathered every other day during the ripening season. Burs that have split open and exposed the brown nuts should be knocked from the trees, and all of the nuts on the ground should be gathered up cleanly. It would be difficult to emphasize too strongly the importance of harvesting the nuts promptly as soon as they are mature. Prompt and careful attention must then be given to the conditions under which they are stored if they are to remain for long in an edible and viable condition.

After the nuts have been gathered[10] they should be held in a layer not exceeding 1 or 2 inches deep for 3 or 4 days. It is important that they be kept in a well-ventilated building and that the sun does not strike the nuts during curing. After the preliminary curing, the nuts should be placed in friction-top metal cans (slip-top cans) and the lids should not be tight for the first month of storage. The nuts contain enough moisture after the short curing process that the lids will "sweat", or surplus moisture will accumulate on the under side. This will disappear slowly by evaporation during the first month or 6 weeks of storage and the lids may then be pushed firmly into place, making the can nearly airtight. The containers of nuts should be held in cold storage at temperatures of 32 deg. to 36 deg.F. While some nuts have kept quite well at temperatures as high as 45 deg.F., the tests indicate that the nearer the storage temperature is to 32 deg.F., the less is the mold development. Placing the cans in an ordinary home refrigerator should prove fairly satisfactory with nuts that have good keeping quality.

[Footnote 10: If the nuts are infected with weevils, they should immediately be treated after harvesting with the hot water or methyl bromide treatment as recommended by the United States Department of Agriculture, Bureau of Entomology and Plant Quarantine.]

It is essential that the nuts be placed in storage immediately after they have had the preliminary curing. Any delay may increase the possibility of mold development.

In the winter of 1945-46, nuts from 6 seedling Chinese chestnut trees were stored separately in five-gallon friction-top cans at the Plant Industry Station, Beltsville, Md., at 32 deg.F. for approximately 6 months. The results are given in Table 1. It will be noted that there was some variation in the percentage of spoiled nuts in the different lots, but the loss was small when compared with results obtained by other methods. All of the sound nuts in these lots were planted in a rodent-proof coldframe immediately after they were removed from storage, and from 90 to 95% germination of the seed was obtained throughout.

It is almost impossible to keep some varieties satisfactorily with even the best of care. Because of the great difference in keeping quality of the nuts of different varieties and from different seedling trees, each chestnut grower should study the keeping performance of the nuts from the different trees in his own orchard. He should save for permanent trees those producing nuts that keep well.

The method of storing chestnuts that perhaps has been more widely used than any other is to pack the nuts in slightly moist sphagnum moss or fresh hardwood sawdust in boxes and place them in cold storage at 32 deg.F. to 34 deg.F. A little less volume of packing material than of nuts is customarily used. The correct amount of moisture may be attained by adding 4 fluid ounces of water to 1 pound of dry sphagnum moss. There is great danger of getting too much moisture, which will tend to cause spoilage. If the cold storage compartment is one that has a tendency to dry the stored material, it may be necessary at some time during the year to open up the boxes and add a little moisture to the sphagnum, but in most storage houses this is not necessary.

Based upon results obtained during the last 2 or 3 years, it seems probable that the method of storing chestnuts in friction-top cans will prove to be more efficient than other methods now in use. Tests are under way to determine the most desirable moisture content of nuts at the time of storage. If this can be determined the present period of preliminary curing will become a matter of reducing the moisture content of the nuts to a known amount before they are stored. It is likely that other refinements of the method will be made in the near future, but the procedure here described has given results that merit further trial by those concerned with chestnut storage problems.

TABLE I—Record of Keeping Quality of Nuts from 6 Seedling Chinese Chestnut Trees Stored In Friction-Top Cans At 32 deg.F. for Approximately 6 Months At Beltsville, Winter—1945-46[11]

====================================================================== Total Weight Weight of Weight of Tree Number of Nuts Sound Nuts Spoiled Nuts Percent Spoiled 4-24-46—Lbs. Lbs. Lbs. ——————————————————————————————————— 7861 23.69 23.08 .61 2.57 7881 25.20 24.63 .57 2.26 7930 26.85 26.48 .37 1.37 7932 24.29 23.80 .49 2.02 7938 29.00 27.48 1.52 5.24 8174 15.82 14.80 1.02 6.45 ====================================================================== ALL LOTS 144.85 140.27 4.58 3.16

[Footnote 11: Weighed and examined 4/24/46.]

Essential Elements in Tree Nutrition

(Paper presented before the Northern Nut Growers Association Convention, September 3-5, 1946, Wooster, Ohio.)

By J. F. Wischhusen Manganese Research & Development Foundation, Cleveland 10, Ohio

Mankind has harbored an age-old grudge against insects and fungi, so that under the heading of crop protection from these pests there has developed a large insecticide and fungicide industry.

Relatively little attention has been paid to the effects of a nutritional character that can be obtained from simultaneous applications of essential elements. Insects will probably always constitute a problem of destruction, either of them or by them. But fungi, bacteriae, viruses, can be made to combat, control and balance each other; depending on the conditions under which their propagation is either facilitated or inhibited.

There is evidence that so-called essential nutrients, also variously referred to as "minor", "trace", "rare", or "micro" elements play a direct as well as indirect role of considerable importance in this matter, and that trees can be fertilized, sprayed, injected or treated with them in other ways to insure their growth, health, crop bearing ability, longevity, disease—frost—and drought—resistance. There still exists a paucity of scientific explanations on these subjects, but there is already a good deal of scattered information, which it is my purpose to draw to your attention. People do not care about scientific facts if they can obtain results without them, and then scientific concepts too may undergo changes. The manner in which trees obtain their nutrients from soil, air and water, however, will forever remain unchanged, whether we understand it or not, and it behooves every grower to observe effects from causes, and to reflect upon them, and report his observations to his association for the benefit of all.

Physical Soil Characteristics

That the primary requisites for tree growing are the physical characteristics of all soils favorable for that purpose requires no discussion. The successful nut tree planting starts with the soil, whether it be on the scale of an orchard, grove, or just a few trees around the farm or garden.

The better soils for general crop production are on limestone, basalt, dolemite, dolerite, diorite and gabbro formations, whereas sandstones, aplites, granites, pierre shale, cretacious rocks and volcanic formations weather into inferior soils. Gneiss can be sometimes good, sometimes unfavorable for building of fertile soil.

It is well to bear in mind that geology and botany are our two fundamental sciences, and that all our other sciences are in reality departments of these. Chemistry can be either a branch of botany if it deals with organic chemistry, or else a branch of geology, if it deals with inorganic chemistry, and it would appear that the modern scientific grower of nut trees or any other crops is wittingly or unwittingly concerned with both. Biology and zoology both are branches of botany.

The Essential Elements

In the past, economics have governed any crop production, whether of trees, grains, fruits or vegetables; not nutrition and health. The future in all likelihood will demand improved crops from the standpoint of nutritional purposes as foods. It is gradually being realized that the production of better crops can be brought about by greater application of essential nutrients to soils or as nutritional sprays direct to trees, and that such practices also reflect true economics. The same principle should govern wood production.

According to our today's knowledge, there are at least nineteen elements invariably essential to life, viz:

Primary: Hydrogen, carbon, nitrogen, oxygen, phosphorus.

Secondary: Calcium, magnesium, sodium, potassium, iron, sulphur, chlorine.

Micro: Manganese, copper, boron, silicon, aluminum, fluorine, iodine.

Then there are another eighteen elements at least variably necessary to life, viz:

(1) Variable Secondary Elements: Zinc, titanium, vanadium and bromine.

(2) Variable Micro-Elements: Lithium, rubidium, caesium, silver, beryllium, strontium, cadmium, germanium, tin, lead, arsenic, chromium, cobalt and nickel.

Elements in Soils Essential for Plant Growth

It is furthermore safe to state at the present time that fertile soils should contain at least the following twenty elements: Nitrogen, phosphorus, potassium, calcium, magnesium, sulphur, hydrogen, carbon, oxygen, iron, sodium, chlorine, aluminum, silicon, manganese, copper, zinc, boron, iodine, and fluorine.

Until quite recently many scientists believed that only the first ten elements were necessary for growth and maturing of crops; that only the first three should be considered as fertilizer ingredients, and that the others were supplied by soil, air and water, or were present as natural fillers in manures and fertilizer raw materials.

The modern agronomist, however, takes all these twenty essential elements into consideration, and many so-called "complete" fertilizers contain at least sixteen to eighteen, if not all of the elements mentioned above. Cobalt, essential to animal nutrition, can also most economically be supplied through the soil, even though crops grow without it.

As long as we have sufficient experimental research data that at least nineteen elements are invariably essential to all life, it stands to reason, that they at least must also be present in one way or another for the normal, or better the optimum growth of nut trees, and a crop of more nutritious nuts. Therefore, every time one of them is considered, all the others must also be borne in mind. It will neither prove difficult nor costly to experiment with them. It is a matter of finding the proper balance of everything essential for optimum nut tree growing.

Indeed, to ascertain the true balance of all elements that are invariably essential to life, and their relationship to the elements which are variably essential, would quite naturally appear to constitute the quintessence of research still to be performed. We cannot control such essential factors as climate, weather, sunshine, but man can control the supply and adjustment of nutrients to trees, and it rests entirely with him to do so.

There is one advantage a nut crop has over some other crops; it does not have to be harvested before fully mature. Nut crops obtain the benefit from elements that may be slowly assimilated during the season.

The following experimental and historical evidence and opinions have come to my attention, and I record them for what interest they may have. Past experience is often discarded as too old, but many a time an experimenter was ahead of his time, and his work remained unrecognized, so that now some old references can be revived and presented as novelties. What the past ignored may indeed be due to the ignorance of those who did the ignoring.

1) The Chestnut Blight

The chestnut blight, for instance, of a generation ago, may be re-examined in the light of the proceedings before a chestnut blight conference, held at Harrisburg, Penna., February 20-21, 1912. A chestnut extract manufacturer, a Mr. W. M. Benson[3], stated at the time that in his experience the best extracts were made from trees high in lime. "A blighted tree," he stated, "is simply a tree in the process of starving to death for lack of lime." Maps showed that the blight was worst where there was least lime, and that the chestnut trees died last in Tennessee, where soils are high in lime. Analysis showed that chestnuts contained 40% lime, an unheard of amount. That this high test may reflect a faulty condition is pointed out later.

All I can add to this is that there is an English Walnut Tree, Alpine variety, on the farm of Mr. Deknatel, on Route 202, Chalfont, Penna., which is remarkable for its virility and crops of large nuts. This tree grows in a place protected by house and barn near a well, in limestone soil. It resisted the severe winters of 1935 and 1936, when many other English Walnuts in the vicinity died. My opinion is that any tree in that location would be an outstanding tree; and vice versa, had that particular tree been planted in another location, it would have done no better than any trees there located. Nuts from that tree might well be tested and compared with nuts from other trees.

2) The Banana Blight

The banana blight in Central America threatened for a while to be as destructive as the chestnut blight in this country. It was due admittedly to an attack by soil fungi, but no fungicide to foliage or to the soil served its purpose. However, the proper restoration of bacterial life in soils to keep the soil fungi in check proved effective. This was a matter not of the presence or absence of any one inorganic nutrient, but of restoring to soils the balance of fertility, an abundance of organic matter as food for bacteriae. Dr. George D. Scarseth, West Lafayette, Ind.[4], is one of those largely responsible for correcting this epidemic. His experience may prove useful to nut growers, so that they may not live in constant fear of another blight epidemic such as the one that exterminated our chestnuts only a generation ago.

3) Tree Nutrition, Microbial

From England comes interesting information about "Tree Nutrition"[5]. Evidence shows that the healthy growth of trees such as pines and spruces is intimately bound up with an association between their roots and fungi present in woodland soil. Poverty in mineral nutrients is no longer regarded as a necessarily critical factor in the failure of growth of trees of this kind, since the associated fungi have at their disposal sources of supply inaccessible to the roots of higher plants.

Experiments carried out during the past ten years at Wareham in England fully confirm the opinion expressed long ago by Professor Elias Melin, Upsala, Sweden, that the growth of trees and other plants on poor soils of the raw humus type is greatly influenced by the root-fungus association. By fostering the appropriate combination it has been possible to carry out successful afforestation of heathland so poor that ordinary cultural methods prove inadequate for the least exacting tree species. Satisfying the mineral requirements of the trees by direct application of fertilizers is not in itself sufficient treatment to ensure continued healthy growth; biological factors also play an essential role in promoting soil fertility. The experiments have shown that failure of the trees to establish a satisfactory biological equilibrium with the necessary fungi is due in this case, not to the absence of these fungi in the soil, but to their inactivation by toxic products of biological origin. The factors inhibiting the activity of the fungi can be removed by the application of comparatively small amounts of organic composts which produce dramatic and lasting effects on the growth of roots and shoots.

The special composts used are prepared from organic materials such as straw, hop waste and sawdust. The mechanism by which they stimulate growth is still obscure. All of them contain small amounts of directly available plant foods such as phosphates and potash, but careful investigation both in laboratory pot cultures and in the field, has shown that these can account for only a relatively temporary effect on growth. It is suggested that the composts act mainly by modifying the course of humus decomposition, thus bringing about drastic changes in the biological activities of the organic substrate of the soil.

This demonstration of the profound influence of biological factors on the nutrition of trees challenges the attention of foresters and has important practical applications. By making use of suitable composts, it will be possible to carry out the successful afforestation of land formerly regarded as wholly unproductive.

For further information see "Problems of Tree Nutrition"[5].

From the two foregoing examples it is seen that in the case of banana blight, fungi had to be suppressed by bacteriae, but that for pine trees on poor English soils fungi had to be activated for proper tree nutrition.

4) Inorganic Tree Nutrients

Other information also from England concerns the use of so-called "minerals" which I prefer to call "essential inorganic nutrients," and name by the element or the compound in which the element is contained. "Minerals", strictly speaking, refers to compounds formed by nature as rocks, ores, brines, salt deposits, etc.

Professor Wallace, Director of Britain's Long Ashton Research Station[6], has laid the foundation for diagnosing mineral deficiencies by leaf symptoms. These are reliable indicators of what nutrients to furnish plants when they are distinct and easily recognized. But for subacute deficiencies, plant analysis and injections are resorted to. Injections of manganese sulphate as pellets into holes drilled in trunks of cherry trees caused orchards that had been barren, to bear heavy crops a few months later.

Manganese, boron, zinc, copper, iron, magnesium also lend themselves quite readily for applications as nutritional sprays, when applied as suitable compounds such as the sulphates. Both spray applications and tree injections have great diagnostic values, because a response to them, if needed is relatively quick. When trees are deficient their foliage will show marked improvement from a spray application within a few days, so that a test can be made on a few trees before an entire orchard is treated. Trunk injections should of course be made during the dormant season for results to show the following summer.

5) Nutritional Sprays

Florida and California lead in the application of nutritional sprays on citrus and other fruit[7]. Vegetables, too, respond remarkably thereto[8]. I see no reason why nut trees likewise should not benefit from them, especially when other spray materials are used. Copper sulphate, zinc sulphate, manganese sulphate, magnesium sulphate, iron sulphate, cobalt sulphate and borax are all compatible with each other and with most other spray materials. Combination sprays seem to perform better, anyway, than single sprays, and the only objection would seem to be that some element is applied that is not deficient. It can be taken for granted, however, that nothing is wasted, even though the benefits may be invisible. Soils benefit in the long run from sprays. One element, even though not noticeably needed, may make another available or it may antidote toxicity of some element present to excess. Indirect results in all likelihood are always obtained.

In Florida, recommendations for spray applications to citrus are made annually[9]. They can be obtained from the Florida Citrus Commission, Lakeland, Fla. A typical formulae is as follows:

3-5 lbs. zinc sulphate | 3-5 lbs. manganese sulphate | per 100 gallons of water or 2-5 lbs. copper sulphate with | other spray material equal amounts of lime. |

1 gallon of lime sulphur or 1-1/2 lbs. of lime is used for every 3 lbs. of sulphate of manganese or zinc.

Cherries, apples, plums are quite responsive to such applications, and I have seen the defoliation of prune trees in New York State corrected with a mixture containing:

Manganese 10% | All as metallic, in the form of hydrated oxides, Copper 10% | and applied at the rate of 4 lbs, for the combination Zinc 5% | material per 100 gallons. Boron 1% | The addition of 2 lbs. lime is optional.

In California a manganese deficiency has been observed on English Walnuts[10], and 5-15 lbs. commercial manganese sulphate was used per 100 gallons of water during late May, through June, to correct this.

Sprays should be applied at ten day intervals until the deficiency symptoms no longer persist.

Plausible reasons for the somewhat quicker action of sprays than fertilizers may be furnished by two prominent authorities:

McCollum[11], one of our foremost nutritionists, first noted the discovery that the leaf of the plant is a complete food, and that none of the storage organs of plants, seeds, tubers, roots, fruits enjoy that distinction. In the leaf, biological processes are most active. It is the site of synthesis of proteins, carbohydrates and fats. The leaf is rich in actively functioning cells which contain everything necessary for the metabolic processes, and they supply all the nutrients which an animal requires. ("All flesh is grass").

Hoagland[12], another authority, writes on this subject thus:

"It is now certain that soils are not invariably capable of supplying enough boron, zinc, copper and manganese to maintain healthy growth of plants. This knowledge has come mainly during the past ten years. Within this period thousands of cases from many parts of the world have been reported of crop failure, of plant disease, resulting from deficiencies of micro nutrient elements…. The statements do not imply that most soils are deficient in any of these elements, but the areas involved are large and important enough to warrant the view that the recognition of micro nutrient deficiencies constitutes a development in applied plant nutrition of major significance.

"When I refer to deficiencies of boron, copper, manganese, or zinc, it is not a question of absolute deficiency in total quantity of the element present in the soil, but rather a physiological deficiency arising from the insufficient availability of the element in the plant; in other words, not enough of the element can be absorbed and distributed in the plant for its physiological needs at each successive phase of growth."

Nutritional sprays under such circumstances may prove the remedy, and we have experimental evidence to support this. Nut trees as is shown by the above mentioned experiment, may respond to spray applications equally as well as citrus, other fruit and vegetables, and effects, too may possess special diagnostic values, showing the need of trees, and therefore also the need of soils on which they are grown.

Investigators are constantly confronted with determining whether foliage shows symptoms of disease or starvation, and whether this is due to a deficiency or an excess of any particular nutrient; whether fungicides inhibit the generation of fungi from the spore state, or whether the plant is fortified from sprays or dusts to become disease resistant, or repellent.

Fungicides are valueless where plant disease is caused by bacteriae which invade the water conducting tubes, (roughly corresponding to the blood vessels of mammals), of plants, tree trunks, etc. and prevent the flow of water and nutrient solutions from roots to leaves. Deprived of water and nourishment, the plants or trees will wilt and die. Where, however, soils furnish these plants with protective inorganic nutrients, such as manganese, copper, iron, zinc, borax, etc. these bacterial diseases are prevented. Similar actions may take place in leaves.

Deficiency Symptoms. Kodachrome Slides.

Many acute deficiency symptoms have been identified by authorities and photographed, and I am able to show Kodachrome slides of the following:

Manganese starvation on Swiss chard, spinach (five illustrations), courtesy of Dr. Robert E. Young, Waltham, Massachusetts.

Apricot, sweet cherry, lemon, onions, peanut, soybean (two illustrations), tobacco (4 illustrations), sugarbeets, walnuts, wheat, all by different authors.

Manganese deficiencies in Indiana on soyabeans, hemp, corn, by courtesy of George H. Enfield, Purdue University.

Manganese on beets (mangels), (4 illustrations), and Romaine lettuce, Nassau County, Long Island. Courtesy of Dr. H. C. Thompson, Cornell University.

Many more are published in "Hunger Signs of Crops," an illustrated reference book popular with scientific farmers and growers[13].

Other deficiencies that have been observed on nut trees are the so-called "little leaf" or "rosette" of pecans and black walnuts[14], which is due to a lack of zinc. Strangely enough, healthy orchards in this case contained a preponderance of fungi, whereas in affected orchards the soil microflora was predominantly bacterial[15].

We now have definite experimental evidence that lime, manganese and zinc are required in appreciable quantities for the growth, health and bearing quality of nut trees. It is well to make sure of these elements in the soils devoted to nut tree planting, but it cannot be emphasized too often that all essential elements and factors should be taken care of; anyone of them may be the limiting factor in crop failure; the one that is absent is always the most important.

In regard to inorganic nutrients, more attention has probably been devoted to citrus trees than to any other tree species, largely because the soils of Florida and California require additions thereof. It would be unfair to say that such main fruit crops as apples, cherries, peaches, plums have been neglected; we merely possess more information on the nutrients of citrus trees than on other tree crops, as far as the micro essential nutrients are concerned. Most orchards and groves are fertilized only with nitrogen, phosphorus and potash, and limed when necessary. Nitrogen can stimulate size of fruit at the expense of quality.

A paper by P. W. Rohrbaugh[16], Plant Physiologist of the California Fruit Growers Exchange, Ontario, California, deals with eleven mineral nutrient deficiencies and their causes, viz: calcium, magnesium, potash, phosphorus, sulphur, nitrogen, iron, boron, zinc, manganese, copper, and this might well be used as a guide for nut trees.

6) Miscellaneous

A few oddities may also be mentioned for anyone inclined to experiment:

From Holland it is reported that an avenue of large handsome shade trees close to a century old, all died in one year, except where a junk dealer had stacked a pile of old metals. The trees had exhausted the inorganic nutrients within reach of their roots in the soil, but the junkpile had replenished them sufficiently, so that those within reach of it kept alive to this day, twenty years later.

A rock mulch is reported to have improved the growth of lime and lemon trees considerably[17], and it would seem that similar experiments should be made on young nut trees, just before bearing age in a comparative test with a check planting. Stones can be selected for the nutrients they contain, and a geologist can easily point out those containing the greatest number of elements. No one could go wrong in placing a few rocks of limestone or dolomite near the base of a tree, and let rain and sunshine, heat and frost attend to the fertilizing in a slow but perpetual manner.

Maple sugar contains manganese[18], showing this as a distinct quality over cane sugar. Manganese and other essential nutrients are known to facilitate the production of proteins[19], and the question of better quality nut production may well be examined from the viewpoint of the indirect effect from activities of soil microbiology by manganese, copper, cobalt and zinc. Some of these elements have also been classed as inorganic plant hormones[20]. "Chlorosis," the yellowing of leaves, may not only be a deficiency symptom of manganese, but also one of iron, copper and magnesium. Lack of manganese can cause a decrease in photosynthesis[21], so much so that in manganese deficient leaves the CO2 assimilation may be reduced to half of normal. Herein, too, may lie the cause of low yields, smaller roots and lowered resistance of those roots to invading detrimental organism.

Contemporary work on soil microbiology may show that manganese and other essential nutrients are perhaps most important in their functions for the preservation and balancing of microbial life and actions in soils. There is where tree nutrition must begin; whatever is neglected in soils can at best only temporarily be adjusted afterwards. After all, deficiency symptoms on foliage show lack of soil fertility, and while we should welcome them for their diagnostic value, our corrective measures to be most economical must be taken on soils.

Transmission of Inorganic Nutrients from Soils to Plants to Animals

Soil analysis and plant tissue tests both have their value, but also their limitations. Many laboratories and experiment stations are equipped to make rapid soil tests, and some engage in leaf analysis. It is important that they be correctly interpreted. For instance, at the Citrus Experiment Station, Riverside, California[22], bark and leaves were collected from healthy and diseased Persian Walnuts. They were analyzed for calcium, magnesium, inorganic phosphate, manganese and iron. A higher percentage of ash was found in the diseased than in the healthy bark, and calcium, magnesium, manganese and inorganic phosphates were also generally higher.

It would be a fallacy I think to conclude therefrom that these elements were not necessary, or were present to excess. They were probably present because they had failed to function properly, due to changes in weather, excessive rains or droughts, and could not eliminate themselves.

We must consider the results from the functions of the essential elements, and discard the popular belief that inorganic nutrients in soils are transmitted from soils to plants, and therein contained for the express purpose of satisfying the need of animals and humans[23].

The plant has only one purpose to perform which is to grow and to reproduce itself, and such is the case with all other forms of life.

Plants contain very often inorganic elements in a form in which they cannot be utilized. It is therefore quite easy to mistake their presence either as a toxicity symptom or as a high requirement, when as a matter of fact these elements are present due to conditions unfavorable to metabolism, and they remained in bark and leaves as end products, in an inert form. Rather than being transmitted from soils to plant, their functions may consist of the formation of enzymes, proteins, hormones, chlorophyll, antibodies, vitamins, in carbon assimilation. When they have served such purposes they are not likely to be present in plants in anything like the amounts or forms as present in soils. They may come into question as catalysts or bio-catalysts, as sources of energy for microorganism, from which their optimum effects have been secured when they are not transmitted at all, causing changes, but remaining themselves unchanged. They are essential in the sense that the elements composing soils, sea, atmosphere are constantly energized, changed and used over and over again to create plant, animal and human life. In this cycle nothing is lost, only changed from old to new generations.