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QUICK POSSIBILITIES IN FRUIT IMPROVEMENT

HOW TO BEGIN AND CARRY ON THE WORK

What kind of tree is that, Mr. Burbank?" Seldom does an amateur visit my experiment farms without asking this question. And very commonly I am led to reply: "Why, it is hardly fair to speak of that as a tree; that is a concentrated prune orchard. If I were to name all the varieties of fruit that are growing on the branches from that single trunk, it would sound like reciting the names from an orchardist's catalog. Nearly all my important experiments in developing a particular variety of plum are made, at one stage or another, in these tree-colonies." And when my visitor, observing now on closer inspection that practically every branch shows evidence of having been grafted, inquires what will be done next season, I explain that a fair proportion of the present branches will be cut away and grafts from other seedlings put in their place for further tests. The usefulness of a tree as the basis of further experiments is not finished by any means when it has once been covered by grafted cions. The same process may be practised over and over. Doubtless no other observation made by the average amateur visitor is matter for greater surprise than this utilization of single trees for the carrying out of vast numbers of experiments. The utility of the method, in the saving of both land and the experimenter's time, is altogether obvious once attention is called to it. Yet relatively few, even among professional fruit growers, have hitherto gauged the possibilities of the method. Of course the average visitor who inspects my gardens has no thought of becoming an experimenter on a large scale, and hence would not have occasion to practise multiple grafting and regrafting on any such scale as that employed at Santa Rosa and Sebastopol. But I call particular attention to this matter of fruit-tree grafting, because there is a lesson in it not merely for the professional fruit grower but for tens of thousands of persons scattered across the length and breadth of the country who have in their gardens a few fruit trees, at present of no apparent value, that might be made to bear in abundance. Moreover, there are other thousands who have on their farms neglected orchards, run riot with weeds and bringing no monetary return whatever, which might be made the most productive and valuable portions of the entire acreage. And in each case the grafting of the cions of good varieties of fruit on the old and otherwise worthless stock is the key to the entire situation.

OLD TREES MADE YOUNG

We shall have occasion in the successive chapters of the present volume to examine in detail the methods of cultivation and possibilities of improvement of the different orchard fruits. Here it may be of service to take a brief general view of the subject. And at the outset I wish to emphasize the possibility of making over the orchard material which is now in hand, so to speak, and which is being so sadly neglected. Reports from all over the country tell the same story. In Ohio, for example, according to the report of experts of the Agricultural Station, there are thousands of acres of idle orchards. The product of apples-the chief orchard fruit-has fallen to less than a fourth of what it was a generation ago. Apple trees themselves are about half as numerous as they were; and this implies that those that remain are only half as productive as the trees of twenty-five or thirty years ago. Such a record, coupled with the fact of an ever-increasing demand for orchard fruits, seems almost incomprehensible. Yet similar reports might be had from numberless other regions where fruit production was formerly a more or less important industry. But fortunately the facts of the situation are now being called to the attention of the general public, in particular by the workers at the agricultural experiment stations. Bulletins are being issued that call attention to the possibilities of rejuvenating the old orchards, and in many regions results of this work are being manifested in the restoration of abandoned orchards. In one county in Ohio, in a recent season, 117 rejuvenated orchards added more than fifty thousand bushels to the apple crop. "In several cases," says the Ohio report, "a net profit of $400 per acre has been secured from an abandoned orchard." The report continues: "It is like reaping where one did not sow, to bring one of these orchards into its own again. An investment in one of these orchards is better than gold mine stock, for there is no 'luck' about it. If there is any risk about operations of this sort, it is because of lack of business capacity and industry. To take a neglected orchard and bring it back to usefulness does not require much capital except in brain and muscle, but it is an achievement worth while." An achievement worth while, the renovation of an old orchard, or even the rejuvenation of a single tree, certainly is. I can gauge something of the growing recognition of this fact from the ever-increasing number of letters that come to me from all parts of the world asking my opinion or advice as to the possibility of restoration to usefulness of trees that their owners not long since regarded as worthless. And I am usually able to assure the questioners with a good deal of confidence that if they go about it in the right way they will not merely restore trees to their former level of productivity, but may make them producers of fruit in such abundance and of such quality as quite to outclass their original record.

HOUSECLEANING IN THE TREETOPS

I need not here enter into details as to the exact methods of operation through which such restoration and rejuvenation of old orchard trees may be brought about. Such details can be given to better advantage in the chapters that deal with individual fruits. But there are a few general principles applicable to the entire class of fruit trees that may be briefly outlined. First and foremost, perhaps, is the matter of cutting away the surplus growth of half dead twigs and branches that a neglected tree is sure to exhibit. These serve to distract the energies of the tree, if the phrase be permitted, and even though they may multiply the number of fruit buds, they will greatly minimize the average size of the fruit itself. Regardless of quality, fruit trees generally cannot bear to advantage unless properly pruned. The process may best be carried out late in the winter or very early in the spring. It is well, as a matter of course, to make clean, sharp amputations, so that the bark of the limb below the cut is never torn. No general rule can be given as to the amount of pruning for any species; much less for any individual tree. But it may be taken for granted that the amateur will usually err on the side of pruning too little rather than too much. Where small twigs are cut away by the pruning knife, it is not necessary to treat the stump; but larger branches, requiring the use of the saw, should have the stump covered with hot wax or paint to protect the injured tissues from the weather during the period of healing. This should not be done immediately, but should be delayed for a week or more until evaporation has dried the tissues sufficiently to allow absorption of the protective material used. In connection with this removal of supplementary branches, which is in effect a sort of housecleaning operation, it will be well to scrape off the rough bark of trunk and limb wherever it scales in such a way as to afford snug retreats for insects. And blemishes of a more important order, such as knotholes and decayed surfaces where limbs have been cut away or broken off in the past, should be carefully excavated, all unsound tissue removed, and the cavity filled with ordinary Portland cement or concrete. The latter process has been variously characterized as tree carpentry and tree dentistry. Both terms are more or less suggestive of the work achieved, regardless of names. The operation may result in prolonging indefinitely the life of a valuable tree that would otherwise soon have decayed beyond restoration. The trunk and branches of the tree having been put in order, thought should be given to its root system. The casual observer is likely to forget that only about half the tree is visible, and that the aerial half is not fundamentally more important than the subterranean moiety. Yet it is obvious that the root system furnishes the all-important source of supply of moisture and mineral matter, lacking which growth could not take place at all, let alone fruit bearing. Of course we cannot get at the branches of the roots to renovate them as we have renovated the aerial branches, nor would they require the same kind of attention if we could. There is no danger that a plant will have too many rootlets, for these are the mouths that reach out into the nutrient earth and take up the chemicals in solution that are part of the materials for the building of branch and leaf and flower and fruit alike. But there is danger that the root system may not develop in the best manner, and there is obvious need that the soil into which the roots penetrate should not be depleted of its nourishing properties. As to the manner of development of the root system, of course it is too late to make radical changes if we are dealing with an old tree. With young trees just starting growth or recently transplanted much may be done, as will be pointed out presently. But with the old tree all that can be accomplished is to see that the root already in is being given a fair chance.

ATTENTION TO THE COMMISSARY DEPARTMENT

To this end the ground about the tree should be cultivated with plow or spade, even at the hazard of destroying a certain number of superficial rootlets. The grass and weeds that have been permitted to spring up in the neglected orchard sap the ground and take the nourishment that the tree imperatively needs. But if the surface soil is turned under this vegetable matter will in itself constitute a fertilizer. Unless the soil is unusually rich this should be supplemented with artificial fertilizers, of which nitrates, phosphates and complete mineral fertilizers often appear to have the best effect in rejuvenating an old orchard. In case the soil is a sandy loam, subject to rapid leaching, it may be desirable to sow a so-called "cover crop" to prevent the too rapid washing away of the plant foods in the rainy season. If a leguminous crop is grown, such as clover, crimson clover, cow peas, or vetch, these crops will in themselves add to the nitrogen of the soil, as their roots have the power of taking this from the air. But it is urged by some eastern orchardists that care should be taken to avoid too much nitrogen. The roots of the tree reach down to rich subterranean sources that are likely to be well supplied with nitrogen, because the nitrates are very soluble and are pretty rapidly leached or filtered into the subsoil. After preliminary treatment it has been found in many states best to sow a crop of clover, often with other perennial grasses, as a permanent crop, which should be cut and all material left on the ground for the protection and support of the orchard. This has been found to be an extremely profitable method both in the old neglected and in the new orchards of New England and in the orchards of the northwestern Pacific coast. A small space about the trunk of the tree should be kept free from grass. The experts of the Indiana Experiment Station recommend as a fertilizer, for soil of fair natural fertility and where a leguminous nitrogen-gathering cover crop such as just suggested may be grown, the additional use of a fertilizer having the following formula: "A thousand to fifteen hundred pounds per acre of a mixture containing one part (100 pounds) each of ground bone, acid phosphate and muriate of potash. On soils that are somewhat exhausted, 125 pounds nitrate of soda may be added in addition. "In order to get the greatest returns from this fertilizer it should be thoroughly worked into the soil. This can be accomplished very well by applying it to the surface just before plowing. The plowing and working of the ground will get the fertilizer pretty thoroughly incorporated, and the tree will soon show the beneficial effect of its presence. Hoe the ground often and keep it cultivated until midsummer, then sow a cover crop that will protect the ground until it is turned under the following spring." After these reformatory measures have been carried out, it remains to guard the trees against the attacks of insects with some protective spray. The particular insect or fungus-destroying mixture required will of course depend upon the individual case. The Bordeaux mixture is doubtless used more than any other single spray for fungus diseases and for the codling moth in apples. A lime-salt-sulphur solution is the general mixture for San Jose scale. In general, it should be recalled that spraying is a preventive measure rather than a cure. Bordeaux mixture, for example, will prevent the appearance of the fungus disease commonly called scab. The attacks of the codling moth may be met in the same manner; but as there is a second crop of these moths, another spraying may be necessary later in the season.

BATTLING THE PESTS

I should add that as to this matter of fighting plant diseases and pests with the spray, as also in the matter of the renovation of neglected orchards, I must offer advice rather at second hand. My own orchards, as a matter of course, have not been neglected. While my orchards are cultivated thoroughly, so that a weed is seldom seen, very little fertilizer is used and rarely any spraying, as my object is to obtain varieties that are immune to fungus and insect diseases, and which will thrive in ordinary soils and under ordinary systems of cultivation. No pampered pets are offered from my grounds for general culture. I would urge any orchardist who operates on a large scale to consider the matter of selecting as far as possible varieties of fruit trees that are more or less immune to disease, rather than to depend on the at best somewhat precarious method of warding off the enemies by spraying. Prevention is better than cure with plants no less than with human beings. But of course the renovator of an old orchard, whose task is at the moment under consideration, must work with the materials supplied him and cannot ignore the fungus and insect pests that attack his trees; although by dint of proper grafting he may hope presently to transform the character of the trees in such a way as to give them partial immunity. The orchardist of the future will have still better ones in these regards.

PLANNING A NEW ORCHARD

So much for the renovation of the old orchard. I have spoken thus at length on this aspect of the subject because of its obvious importance, and because it aims at the correction of a widespread condition and has to do with the possible restoration of properties in the aggregate of enormous value. It takes time to grow a tree, and it is peculiarly fortunate that the would-be fruit grower can secure almost anywhere an abandoned orchard that may almost immediately be restored to a condition of productivity. But of course the orchardist who wishes to operate on an extensive scale will not be content with the renovation of an old orchard, however lucrative that process may prove, but will wish to produce a new orchard that may lack the defects of the old one. The ancient tree made over will still retain, in such important matters as height and spread of limb, the evidence that it really belongs to a past generation, however insistently the fruit that its grafted branches bear may seem to belie the evidence. But the trees of the new orchard may be trained in accordance with modern ideas; and it is not to be denied that ideas as to tree pedagogy have changed as rapidly in recent years as have the best conceptions of human pedagogy. Take the very important matter of height of tree as a case in point. Not long ago the orchardist, in developing a young tree, was careful to see that it was trained in the nursery so that its lowest branches were several feet from the ground. But the well-informed orchardist of today heads his tree in such a way that the bearing branches start only eighteen inches or two feet from the ground. Where formerly high ladders were required to pluck the fruit, a modern orchardist, for a good many years after his trees are in bearing, can stand on the ground and reach the main bulk of the fruit; and even that which falls is not mutilated and bruised as it used to be. Also the trees are much less apt to be broken or blown over by the wind. And in this I am not referring to such "freak" trees as, for example, my little bush-like quinces, scarcely waist high yet almost breaking under the weight of mammoth fruits. I am speaking of the commercial orchard, and have in mind in particular the apple tree, because it is with regard to this tree that the most conspicuous transformation has been effected. Plum trees and peach trees were never very large, but it used to be taken for granted that the apple tree should be of gigantic proportions; so the half dwarf trees on which the best apples of today are grown might seem to the casual observer to belong to a different family of plants from their progenitors.

GAUGING YOUR CLIMATE

As to other desirable qualities, much depends upon the location of the orchard and the market that the orchardist has in view. It goes without saying that the varieties to be selected must be of a character adapted to the climate and soil of the chosen region. As to this, the restrictions imposed by Nature are more or less familiar to every fruit grower. In general, you may judge to a certain extent from observation of what is already grown in your neighborhood as to what kinds of trees will thrive there. The chief restrictions are those imposed by conditions of temperature, and of course temperature is influenced not merely by the latitude but by distance above the sea level and the neighborhood of large bodies of water. The presence of moisture in the air has a protecting influence, chiefly in that it prevents radiation of heat at night. Every orchardist knows that the danger from frost increases in proportion as the night is clear. The now familiar method of fighting frost by burning brush or oil supplies direct heat, but also supplements this by filling the air with smoke, which retards the radiation of heat. It is familiarly known that seaboard regions have much milder winters than inland regions of the same latitude. Again, inland regions of low altitude, such as the Mississippi Valley, may be adapted to the growth of a fruit that would inevitably winter-kill if grown on the high plateaus of Wyoming. In general, it may be said that no region at higher altitude than about six thousand feet is adapted for fruit growing. In putting out catalogs of new fruit it is often desirable to state the minimum temperature that a new production will stand. I have done this, for example, in announcing my spineless cactus. As to average annual temperature, it may be convenient to recall that there is likely to be a mean annual difference of three degrees for each hundred miles of latitude. Thus, for example, the mean temperature at the southern line of Iowa will be found to be about three degrees lower than the mean temperature at the northern line; and this difference might, in case of a given fruit, make it folly to plant in northern Iowa a fruit that might live in the southern part of the state. As already pointed out, however, one of the main objects of the plant developer today is to produce hardy varieties, and doubtless it will be possible in the future to grow most varieties of orchard fruits in regions that are now regarded as lying wholly beyond the northern limits of their possible culture.

STUDYING YOUR MARKET

Of course the proximity of the market is an item of chief importance. Yet the experience of the California plant developer may be cited as showing that nearness to market is by no means an absolute essential. For of course it is well known that the California fruits are now chiefly grown for shipment to the Atlantic seaboard. So nearness to a railroad is even more important, as hauling fruit for any great distance before it is packed for eastern shipment is a great detriment to its shipping and keeping qualities. Except in a few cases, like that of the prune, it is always necessary for the California plant developer to consider the shipping quality of his fruit. A fruit to be shipped a long distance must be of firm flesh, a good color, and a reasonably tough skin. And especially it should be uniform in size and of such shape as to admit of economical packing. Moreover, it should ripen at a season when the same kind of fruit is not abundant in the distant market. So it may happen that a fruit otherwise valuable may lack this essential marketing quality, and hence must be avoided. This is the reason why my Abundance plum is not so popular in California as it is in the Eastern States, as it will not stand a long shipment so well as other varieties. To the eastern fruit grower this is not important, as he lives near the market. But from the California standpoint, such plums as the Wickson, the Burbank, the Formosa and the Climax, all of which are excellent shippers, are generally preferred. The advantages of entering the market at a particular season are illustrated by the Burbank cherry, which ripens so early that it reaches the eastern markets when almost no other fruit is on hand. The fact that these cherries often bring two or three times the market price to be secured a few weeks later shows the practical importance of this detail. Another seemingly minor point that the prospective orchardist should not overlook is the question of the color of the varieties of fruit he is to select. Color is one of the most important characteristics of the fruit from the market man's standpoint. The purchaser at the fruit stand will very generally pick out the highly-colored fruit without considering its quality. The prospective fruit raiser should bear this in mind in selecting his stock.

THE ORCHARD SITE

In dealing with an old orchard the fruit grower must obviously take the trees as he finds them. But in developing a new orchard he should give very careful attention to the exact topographical conditions. The matter of drainage of the soil is important, and also the question of exposure to the sunlight and wind. If your orchard site slopes toward the south, and does not lie in the shade of mountains nor where it is subject to the equalizing influence of a large body of water, the trees are likely to be so stimulated by the nearly perpendicular rays of the sun as to blossom before the time of the last frost. Early blossoming might at first thought be considered an advantage; but in point of fact it is a general rule that plants which blossom early ripen their fruit late, whereas those that blossom late are usually early ripeners. The obvious explanation is that the trees that flower late and ripen early have had to adapt themselves to short seasons. The wisdom of their course is emphasized when we see the early blossoms of trees on a southern slope cut off by a late frost, while trees otherwise situated in the neighborhood have not yet come to blooming time. The danger of entire loss from late frosts may be obviated, however, by the selection of varieties that will mature fruit even after the blossoms have been frozen. I have developed such varieties of fruit trees in a number of instances. There are also varieties that have a long blooming season, and these may be depended upon to put forth new blossoms even if the earlier ones were blasted. But in general it is desirable to select a variety of tree that naturally blooms late enough to avoid these frosts. This is especially important in view of what has just been said about frosts waylaying trees on a southern exposure, because precisely such exposure is of value at the other end of the season, to hasten the ripening of the fruit. This is not only important in the case of fruits designed to meet an early city market, but it applies to many varieties that tend to ripen late in the fall and which thus may suffer from the early frosts of autumn. It should be recalled that the warm southern exposure also tends to take the moisture from the soil early in the season, so varieties planted in such a location should be able to resist drought. Trees planted on a hillside will probably have natural drainage. Otherwise it may be necessary to drain the soil with tile or with open ditches, or else to select varieties of fruit that are known to thrive in a moist, cool soil. Such varieties must necessarily have an unusually large leaf surface and shallow root system. For this reason they should not be placed where they are subject to heavy winds. What may be called air drainage is sometimes quite as important as water drainage. Cold air flows down the hillsides and settles in the valleys. So the bottom of a valley is a very poor place to plant fruit; except, indeed, in certain canyons or gulches where there is a steady current of air in motion throughout the night. In general, the orchard site should be on a hilltop or hillside, or at least at an elevation above the lowest land surface in the neighborhood, unless the valleys are either naturally or artificially well drained. Without attempting further details in this place, enough has been said to show that there are almost numberless points to be considered by the up-to-date fruit grower in the development of a new orchard. What has been said will supply clues that the thoughtful orchardist may readily follow up. As to the specific fruits, further details, with particular reference to the practical aspects of the subject, will be given in succeeding chapters.

-"In several cases," says the Ohio report, "a net profit of $400 per acre has been secured from an abandoned orchard."

This text is from: Luther Burbank: his methods and discoveries and their practical application. Volume 4 Chapter 2