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There is perhaps no other wild plant producing a really delicious food product that has been so totally neglected by the cultivator as the shagbark or shellbark hickory tree. The better varieties of hickory-nuts always find a ready sale in the market, and are highly prized by the housekeeper. But such nuts as find their way to the market are almost without exception the product of wild trees, gathered usually by some wandering boy, and often regarded as the property of whoever can secure them, regardless of the ownership of the land on which the tree grows. Even the new interest in nuts as food products and as orchard crops that has been developed in our own generation, has not as yet included the hickory, or at least has not sufficed to bring the hickory tree from the woods and give it a place within the territory of the orchardist. The reason for this, doubtless, is that the hickory is a tree of very slow growth, and that it is also exceedingly difficult to propagate by budding or grafting, or any other process except from the seed. The prospect of improving the product of a tree that does not bear until it is ten or fifteen years old, and that resists all efforts to force it to early bearing, is not alluring, considering the short span of human life. Yet we can scarcely doubt that the hickory nut will presently be brought within the ken of the plant experimenter, and that there will ultimately be developed nuts of very choice varieties, comparable in size, probably, to the English walnut, and having a quality that will place them at least on a par with any other nut now grown in the temperate zones. Even in the wild state, the best of shellbark hickories bear nuts of unchallenged quality. It is a matter of course that these nuts can be improved by cultivation and selective breeding. Material for such selective breeding is furnished abundantly by the wide variation of hickories in the wild state. I had observed this variation in my boyhood days, just as I had noted the variation in the chestnuts. The shagbark hickory, doubtless the best of the tribe, was quite abundant along the banks of the Nashua River near my home, and I early learned to distinguish the great difference in the products of the trees, all of which, of course, were natural seedlings. Among hundreds of trees there would be scarcely two that bore nuts of precisely the same appearance and quality. Some of these hickory nuts were long and slender, with prominent ridges; some were short and compact and smooth in contour; some were very flat and others were nearly globular. The shell varied correspondingly in thickness, and the meat varied greatly in whiteness and in flavor. As a boy I knew very well which trees to seek in the. fall in order to secure nuts that were plump and thin-shelled, with sweet and delicious meats. It was only after the crop of these trees had been gathered that inferior ones gained attention. I knew very well, also, that different trees varied greatly in productiveness, some bearing nuts so abundantly each year that the ground was literally covered when the nuts fell. Others produced nuts very sparingly. The trees that thus varied as to their fruit, varied also in form, in size, and in rapidity of growth. In a word, the wild hickories represented numerous varieties that a boy could differentiate, whether or not a botanist might choose to classify them- as members of the same species. All these varied members of the shagbark tribe bore nuts that had an unmistakable individuality of flavor that distinguished them from any other nuts. Much as they varied in size and degrees of excellence, all of them were hickory nuts, and could be mistaken for nothing else. There were, however, other hickory trees growing in equal abundance on my father's place, though they differed essentially in appearance from the shagbark nuts, that produced nuts of a far less interesting character. Hickories of this kind were locally called pig-nuts. They are classified by the botanist as Hicoria glabra. The trees of this species are more upright and symmetrical, and of much more rapid growth than the shagbark. The nut has a thin husk-like shell, but the meat is difficult to remove, and is so ill-flavored that it is little prized by any one. Indeed, the nuts are usually not gathered at all if shagbark hickories of any quality can be obtained. Nevertheless, there was great diversity among the pig-nuts no less than among the hickories of the better species. So with these also there is doubtless opportunity for improvement through selective breeding, although up to the present time no comprehensive experiments in this direction have been made. I have now little doubt that some of the variant hickories that I knew as a boy were hybrids. The two species of hickory are closely related, and I have reason to believe hybridize not infrequently in the wild state. I have received specimens of hickory nuts from different parts of the United States that I feel certain were natural hybrids. And I entertain no doubt that such hybridization occurs not infrequently. It is probable that when the attempt is systematically made to develop the hickory nut the method of hybridizing the two species will be employed to give still wider variation and to facilitate a wider selection.


There is a variety of the hickory nut that grows in the valleys of the Mississippi and the Ohio that is of relatively enormous size. The shell of this variety, however, is thick, and the meat is not generally as fine in flavor as that of the eastern shellbark hickory. But the size of this wild variety gives assurance that under cultivation and selection the nut may be made to take on proportions that will be very attractive. Doubtless the comparatively small size of the wild hickory nut has led to its neglect, although we must recall that the walnut and the butternut have also been neglected, notwithstanding their much larger size. The chief reason why these nuts have been overlooked, doubtless, is that the idea of making nuts a cultivated crop, comparable to orchard fruits, has only recently been conceived in America-or at all events has only recently been given general recognition. It is not improbable that it may be found feasible to hybridize the hickory with the black walnut or the butternut. These trees, to be sure, do not belong to the same genus, but they are not very distantly related, and we have seen that generic bounds do not necessarily constitute impassable barriers. Could hybridization be effected between the hickory and either the walnut or the butternut, the product should be a nut of very great value. It would be necessary, of course, to breed selectively, doubtless for a number of generations, to secure size and quality, and in particular to develop a race of thin-shelled nuts. But that all this may be accomplished cannot greatly be in doubt. In any event, the experiment is well worth making. There is reason to expect that the next three or four generations will see somewhat the same rapid progress in the art of developing the nut-bearing trees that has been witnessed in the past three or four in the development of orchard fruits. And certainly the hickory nut, walnut and butternut constitute better native material than the wild plums, for example, with the aid of which some of the finest varieties of cultivated plums have been developed within the most recent years. And, indeed, it must not be forgotten that the work of developing our native nuts has already passed the experimental stage with regard to at least one species. This is the nearest relative of the hickory, a member indeed of the same genus, which is familiar as the pecan. This nut grows only in the southern parts of the United States, being far less hardy than the other hickories. But what it lacks in hardiness it makes up in quality, and it is pretty generally regarded as the best nut that is grown in temperate climates, not even excepting the English walnut. The relationship between the northern hickories and the pecan is attested by the fact that in the regions where the two tribes intermingle, they hybridize freely. I have received specimens of the nuts that were undoubtedly hybrids between the shagbark hickory and the pecan, and these included two or three varieties that are among the finest nuts that I have ever seen. The seedlings that grew from them included two trees that gave great promise. Unfortunately the gophers destroyed them both. So the experiments I had contemplated in connection with them were not carried out. But I am confident that great improvements in the pecan wvill result from hybridizing this nut with the shagbark hickory.


Even in its existing varieties, however, the pecan nut has very attractive qualities; and it has the distinction of being the only native nut that has hitherto been placed under cultivation on an extensive scale and has attained commercial importance. We have already referred to the economic importance of this nut in an earlier chapter, and mention was there made of the fact that all the pecans now under cultivation are directly derived from a few wild varieties that have been propagated by budding and grafting. It is only in recent years that a method of grafting this nut successfully has been developed, and as yet little or nothing has been done toward improving the wild varieties. The fact that the nut in its wild state has such attractive qualities gives full assurance that under cultivation and development it will prove of even greater value. In selecting the best wild varieties for cultivation, attention has been paid to the matter of early bearing, and in particular to persistent bearing. So the orchards that have recently been started are stocked with trees that may be expected to bear crops of nuts in about seven or eight years, and that may be depended on to produce a crop each year with reasonable certainty. But as to both time of bearing and regularity and abundance of production, there is still opportunity for much improvement. Doubtless improved varieties may be secured through mere selection by raising seedlings from the nuts grown on trees that were especially good bearers. But it is probable, also, that the full possibility of the pecan will not be realized until extensive series of hybridizing experiments have been carried out. I have spoken of the natural hybrids between the pecan and the shagbark hickory. Hitherto, no extensive experiments in hybridizing these species have been carried out, although it is possible that some of the wild varieties of pecans that have been brought into the orchard were natural hybrids. It is to be hoped that experiments along this line will be taken up in the near future, but, of course, many years will be required before notable results can be attained. It is desirable, also, to attempt hybridizing the pecan with the butternut and walnut, and with the English walnut and the Japanese walnut. If hybridization could be effected, it may be expected that trees of rapid growth, similar to my hybrid walnuts, will be produced. Not unlikely some varieties that tend to produce nuts at a very early age, like my hybrid chestnuts, may also appear as the result of such combinations. And in any event it may confidently be expected that new varieties will give opportunity for wide selection, and for relatively rapid improvement in the qualities of the nuts themselves. We have learned that the pre-eminent qualities of our various cultivated fruits have largely been given them by hybridization. The contrast between the tiny beech plum, for example, and its gigantic descendant a few generations removed, offers an object lesson in the possibilities of fruit development by hybridizing and selection. And, for that matter, each and every one of our improved varieties of orchard fruits teaches the same lesson, even though the wild progenitor is not at hand for comparison. So there is every reason to expect that the wild pecan will similarly respond to the efforts of the plant developer, and that its descendants, a few generations removed, will take on qualities that even the most sanguine experimenter of today would scarcely dare to predict. One improvement that might probably be secured without great difficulty is the introduction of the quality of hardiness, so that the pecan might be cultivated farther to the north. At present the pecan does not produce profitably as a rule, even in the coast counties of California, as the nights are too cool, thus making the season too short for the pecan to ripen its fruit. About Vacaville they thrive much better, and the Sacramento and San Joaquin Valleys, where the nights are very warm, there is as good prospect of growing the pecan profitably as anywhere else in the world. But in the main the cultivation of this nut has hitherto been restricted to the region of the Gulf of Mexico. It is obviously desirable that so valuable a nut should be adapted to growth in wider territories. The fact that the pecan will hybridize with the hardy hickory obviously points the way to the method through which this end may be attained. The peculiarity of the hickory and pecan that is associated with their long life and slow growth, is the fact that during their first year the seedlings mnake perhaps 99 per cent. of their growth under ground. They produce enormous roots before they make any appreciable growth above ground. It is nothing unusual to find pecan seedlings an inch high with roots from four to six feet in length, and an inch in diameter at the widest part. Such a root system prepares the tree for the strong growth that characterizes it later; but a seedling that makes only a few inches of growth in the first season is a rather discouraging plant from the standpoint of the cultivator. Doubtless the pecan may be induced to change its habit in this regard by hybridizing. The example of the hybrid walnuts may be cited as showing that a tree that is ordinarily slow of growth may be made to take on the habit of very rapid growth without relinquishing any of its other characteristics of hardiness and the production of valuable timber. The case of the Royal walnut shows also that the tree that thus becomes a rapid grower may also have the habit of enormous productivity. If the pecan could similarly be stimulated to increased rapidity of growth, and to a proportionate capacity for nut bearing, this tree would be a fortune-maker for the orchardist. And there is no obvious reason why the pecan should not have the same possibilities of development that have been demonstrated to be part of the endowment of its not very distant relative, the walnut.


There is yet another native American nut as hardy and as widespread as the hickory, that has been even more persistently neglected. This is the familiar hazelnut. There are two familiar types of hazelnut that often grow in the same region, and that resemble each other so closely that the boys who gather the nuts commonly do not discriminate between them. One of these grows in husks with a long beak, while the other has an incurved husk that in some cases does not fully cover the nuts. There are sundry varieties of the two species that may sometimes be found growing in the same patch. The fact of such variation in the wild species is of course important from the standpoint of the would-be plant developer. We have learned from frequent repetition that where there is variation there is opportunity for selection and improvement. The hazelnut has a European relative that is as familiar in America as the filbert. This is merely a larger hazelnut, the qualities of the two nuts both as to form and flavor being such as to leave no question of their relationship. But for some reason the European nut appears not to thrive in this country. At all events it has never been cultivated here on a commercial scale. But for that matter the hazelnut has never been cultivated on a scale commercial or otherwise, unless in the most exceptional instances when it has been brought into the garden by some one rather as a curiosity than for any commercial purpose. Yet the nut is a really valuable one, and certainly it is one that would repay cultivation and development. Attempts have been made to grow the European filbert in Sonoma County, California, both from seed and from division, but in all cases these attempts have failed. The purple-leaved hazelnut grows and thrives here in California as it does almost everywhere else in the United States. The species known as Corylus rostrata grows wild rather abundantly in certain sections, but so far as I have observed, it is a shy bearer. There is no obvious reason why the European filbert should not be cultivated in this country if a study is made of its needs as to soil and climate. Also, there is no seeming reason why it should not be hybridized with the American hazelnut. The result of such hybridizing, if we may draw inferences from analogy, would be the production of a race of hazel-filberts of greatly increased size, and of improved quality. There is a so-called filbert, or Chilean hazelnut, that grows in South America. This plant bears a nut similar to the filbert, but much larger in size and of far better quality. It is difficult, however, to get a start in the cultivation of this plant, as its seeds when brought to this country ordinarily do not germinate. I have at last succeeded, however, in producing several young trees. The nut is four times as large as the hazel nut. This is a beautiful tree, and should prove of great value. In its own country the plant is very highly prized, selling for a large sum when only a few inches high. The European filbert grows readily from the seed, but does not by any means come true. Indeed, it proves exceedingly variable. But this, of course, from the standpoint of the plant developer could not be regarded as a fault. If through selective breeding a variety could be produced that would bear regularly and abundantly, and in particular if the size of the nuts was increased, this would be one of the most important of all nuts. As yet, however, a variety that is adapted to growth in this country has not been produced. So there is abundant opportunity for work on the part of the plant experimenter. With the American hazel and the European filbert for material-whether or not further aid may be expected from the Chilean species-there is opportunity to produce a nut that will amply repay almost any experimenter for the time and labor that may be spent upon it.


A nut that has come to be fairly well known in the market in recent years, but which has hitherto scarcely been grown in this country, is the Pistachio. The tree on which this nut grows is a member of the sumac family. The nuts are small, but on the best trees are produced in profusion. In recent years the Department of Agriculture of the United States Government has imported a great number of plants and seeds of the pistachio, which are now being grown experimentally, and which, it is hoped, will form the basis of an extensive culture of this nut. The experiment has not as yet progressed far enough to make prediction possible as to the results. My own experience with the nut is limited to the growing of a single plant about twenty-five years ago, which, after I had cultivated it for a dozen years was found not to be a fruiting variety, and so was destroyed. An Australian tree-shrub or small tree, called the Macadamia ternifolia, has been introduced in California in recent years, and is regarded as a valuable acquisition. The tree is ornamental, and it bears a fruit that is regarded as of value. At the center of the fruit is a round, delicious nut, much larger than the ordinary filbert, indeed, sometimes almost equaling a small English walnut, that is fully equal in flavor to the best filbert or almond. The Macadamia has proved hardy in this vicinity, but requires a well-drained soil. A wet winter is very destructive to the trees, unless they are on dry, well-drained land. There are several species of Macadamia, the one that I have raised most extensively being known as Macadamia ternifolia. This is a handsome evergreen, the leaves of which resemble those of the magnolia, but are thinner and rougher. The nuts are often an inch in diameter, with rather thin shells, and large, round, delicious meats. Further tests will be necessary before the climatic limitations of the Macadamia are fully established. But in regions where it can be grown, it must prove a nut of very great value.

-The prospect of improving the product of a tree that does not bear until it is ten or fifteen years old, is not alluring, considering the short span of the human life; yet we can scarcely doubt that even the hickory nut will presently be brought into the dominion of the plant experimenter.

This text is from: Luther Burbank: his methods and discoveries and their practical application. Volume 11 Chapter 5