Tree Crops: A Permanent Agriculture

by J. Russell Smith, Sc.D.

Chapter II -- Tree Crops -- The Way Out

Again I stood on a crest beneath a spreading chestnut tree, and scanned a hilly landscape. This time I was in Corsica. Across the valley I saw a mountainside clothed in chestnut trees. The trees reached up the mountain to the place where coolness stopped their growth; they extended down the mountain to the place where it was too dry for trees. In the Mediterranean lands, as in most other parts of the world, there is more rainfall upon the mountains than at sea level. This chestnut orchard (or forest, as one may call it) spread along the mountainside as far as the eye could see. The expanse of broad-topped, fruitful trees was interspersed with a string of villages of stone houses. The villages were connected by a good road that wound horizontally in and out along the projections and coves of the mountainside. These grafted chestnut orchards produced an annual crop of food for men, horses, cows, pigs, sheep, and goats, and a by-crop of wood. Thus, for centuries, trees upon this steep slope had supported the families that lived in the Corsican villages. The mountainside was uneroded, intact, and capable of continuing indefinitely its support for the generations of men.

Why are the hills of West China ruined, while the hills of Corsica are, by comparison, an enduring Eden? The answer is plain. Northern China knows only the soil-destroying agriculture of the plowed hillside. Corsica, on the contrary, has adapted agriculture to physical conditions; she practices the soil-saving tree-crops type of agriculture.

Man lives by plants. Plants live in the soil. The soil is a kind of factory in which the life force of plants, using plant food from earth, air, and water, and assisted by bacteria and the elements of the weather, changes these natural elements into forms that we can eat and wear, manufacture and burn, or use for building material. This precious soil from which we have our physical being is only a very thin skin upon the earth. Upon the hills and mountains it is appallingly thin. In some places there is no soil at all, and rocks protrude. Sometimes the earth mantle may be only a few inches in depth; rarely does the soil on hill or mountain attain a depth of many feet. Often soil is so shallow that one great rainstorm can gash and gully a slope down to bare rock. Where man has removed nature's protecting cover of plants and plant roots, the destroying power of rain is increased a hundredfold, a thousandfold, even at times a millionfold, or perhaps even more than that.

The creation of soil by the weathering of rock is a very, very slow process. In some places, centuries and millennia must have passed in making soil that, if unprotected, may be washed away in an hour. Therefore, today an observer in the Old World might see myriad landscapes once rich with farms where now only poverty-stricken men creep about over the ruined land, while their sheep and goats, scavengers and destroyers, pick the scanty browse that struggles for life in the waste. A handful of men are now living uncomfortably where once there were prosperous villages. Similar examples, even of large areas, can be found in almost any hill country with a long history of occupation by agricultural man.

Syria is an even more deplorable example than China. Back of Antioch, in a land that was once as populous as rural Illinois, there are now only ruin and desolation. The once-prosperous Roman farms now consist of wide stretches of bare rock, whence every vestige of soil has been removed by rain.

Geikie, in modern times writing of a section of Palestine, gives a similar example, which shows the ruination that man can create:

Greece, once so great, is shockingly ruined by soil wash. Its people undernourished and living (1949) on the American dole (Marshall Plan). Wolf von Schierbrand, in his book Austria Hungary (Chapter 14), says that in parts of Europe, people even pound stone to get a little bit of loose material in which plant roots can work.

In our own South, millions of acres are already ruined. "Land too poor for crops or grazing, such as old abandoned fields, of which Brazos County [Texas] alone has thousands of acres." (H. Ness, Botanist, Texas Experiment Station, Journal of Heredity, 1927.) The same destructive agency has caused ruin and abandonment of land in Ohio, Illinois, Indiana -- indeed, in every one of our States. "In many sections of Iowa, Missouri, Nebraska, and other Corn Belt states, water erosion has a tendency to form deep, steep-sided ravines which will sometimes make farming almost impossible in a field as large as twenty or forty acres." (Letter, Ivan D. Wood, State Extension Agent, Agricultural Engineering, University of Nebraska, July 19, 1923.)

This is double danger. First, water erosion destroys soil. Secondly, it cuts up the remnant so that it cannot be used by the new machinery which cries aloud for room and good surface. And yet., as human history goes, we came to America only yesterday.

If we think of ourselves as a race, a nation, a people that is to occupy its country generation after generation, we must change some of our habits or we shall inevitably experience the steadily diminishing possibility of support for man.

Flat-land Agriculture Goes to the Hills

How does it happen that the hill lands have been so frightfully destroyed by agriculture? The answer is simple. Man has carried to the hills the agriculture of the flat plain. In hilly places man has planted crops that need the plow; and when a plow does its work on lands at an angle instead of on flat lands, we may look for trouble when rain falls.

Whence came this flat-land agriculture of grass and grains? The origin of wheat, barley, and most of our important food plants is shrouded in mystery; but we know that our present agriculture is based primarily on cereals that came to us from the unknown past and are a legacy from our ancient ancestress -- primitive woman, the world's first agriculturist. Searching for something to fill little stomachs and to hush the hunger cries of her children, primitive woman gleaned the glades about the mouth of her cave. Here she gathered acorns, nuts, beans, berries, roots, and seeds.

Then came the brilliant and revolutionary idea of saving seed and planting it that she might get a better and more dependable food supply. Primitive woman needed a crop in a hurry, and naturally enough she planted the seeds of annuals, like the ones that sprouted around the site of last year's campfire. Therefore, we of today, tied to this ancient apron string, eat bread from the cereals, all of which are annuals and members of the grass family.

As plants, the cereals are weaklings. They must be coddled and weeded. For their reception the ground must be plowed and harrowed, and sometimes it must be cultivated after the crop is planted. This must be done for every harvest. When we produce these crops upon hilly land, the necessary breaking up of the soil prepares the land for ruin -- first the plow, then rain, then erosion. Finally the desert.

Can We Get Economics into Botany?

Must we continue to depend primarily upon the type of agriculture handed to us by primitive woman? It is true that we have improved the old type. Many of the present-day grains, grasses, and cereals would scarcely be recognized as belonging to the families that produced them. Indeed the origin of corn, and of some others, is still in doubt. Present-day methods of cultivation but dimly recall the sharpened stick in the hand of primitive woman. But we still depend chiefly on her crops, and sad to relate, our methods of which we are so proud are infinitely more destructive of soil than were those of the planting stick in the hands of Great-Grandmother ninety-nine generations back.

We are now entering an age of science. At least we are scientific in a few respects. It is time that we made a scientific survey of the plant kingdom -- still the source, as always, of a very large proportion of that which is necessary to the existence and comfort of man and without which we would all be dead in a year. We should carefully scrutinize types of agriculture in relation to environment. Agricultural America should scientifically test the plant kingdom in relation to potential human use and do it as carefully and patiently as industrial America has tested cement. We test cement in every possible way, make it of all possible materials, mix all possible combinations, test it by twisting it, pressing it, pulling it; test it thousands of times, hundreds of thousands of times, perhaps even millions of times, and in a few years our whole physical equipment is made over by reenforced cement made possible by these millions of tests.

The Tree an Engine of Nature -- Put it to Work

Testing applied to the plant kingdom would show that the natural engines of food production for hill lands are not corn and other grasses, but trees. A single oak tree yields acorns (good carbohydrate food) often by the hundredweight, sometimes by the ton. Some hickory and pecan trees give us nuts by the barrel; the walnut tree yields by the ten bushels. There are bean trees producing good food for cattle, which food would apparently make more meat or milk per acre than our forage crops now make. It is even now probable that the king of all forage crops is a Hawaiian bean tree, the keawe. (See Chapter 5.)

These wonders of automatic production are the chance wild trees of nature. They are to be likened to the first wild animal that man domesticated and to the first wild grass whose seed was planted. What might not happen if every wild crop-bearing tree was improved to its maximum efficiency? Burbank and others have given us an inkling of what may result from well-planned selection, crossing, or hybridizing.

The possibilities, at present quite incalculable, that lie in such work are hinted at in one almost unbelievable statement of the great authority, Sargent, who says of the English walnut, which we all know is so good and meaty:

The "careful selection" to which Sargent refers must be the habit of the (perhaps) illiterate farmer in picking out good nuts to plant. The crossing of such plants standing side by side is real plant breeding, and the result is our splendid English walnut. I have grown Chinese chestnut trees that bore nuts and good ones too, in their second growing season. The origin of the seed was similar to that suggested for the above mentioned walnuts.

We now know how to breed plants. In the short space of a few years we can surpass the results of centuries of chance breeding. The plant kingdom has become almost as clay in the hands of the potter. Where we now have one good crop plant, we may some day have five or ten. We need to start in earnest to apply some of our science to producing genius trees -- trees that are to other trees as human geniuses are to other men.

Genius trees produced either by chance or design can be propagated a million or ten million times, as was done with the one chance navel orange tree.

If you want to get a look-in on plant breeding, see the Yearbook, United States Department of Agriculture, for 1936. You will find hundreds of pages of it.

So much for better trees, but I wish to suggest a little-explored line of experimentation that may improve the productivity of the trees we now have -- girdling, ringing, or otherwise injuring the tree in such a way that it will recover the injury but will, because of it, yield a large quantity of fruit. This is a regular practice of the Greek growers of a grape that enters the world market under the name of currant. It appears that the quantity of fruit a tree bears is in part a matter of habit. One tree bears every year. Another bears every other year. One tree, say the York Imperial apple, will average twenty bushels per year, while a Spitzenberg, just as large and standing beside it, may possibly average five bushels. Girdling makes many trees produce. I have no idea that most trees bear all the fruit they are physiologically capable of producing. Careful experimentation along this line might be very productive.

The Tree a Better Crop Plant

We need a new profession, that of the botanical engineer, which will utilize the vital forces of plants to create new mechanisms (crop-yielding trees) as electrical and mechanical engineers use the forces of electricity and the elements of mechanics to create new mechanisms for the service of mankind.

This creation of new types by plant breeding depends upon three facts -- first, the variation of different offspring from the same parents; second, the varying combinations in offspring of the qualities of the parents; and third, the appearance in offspring, especially hybrid offspring, of qualities possessed by neither parent.

First, variation of offspring. Look at the children of almost any family you know. This tendency to variation runs deep into both animal and plant life. For example, Texas Agricultural Experiment Station, Bulletin 349, "Variation in certain lint characters in a cotton plant and its progeny," shows that the average length of lint in the individual plants of the progeny of a certain boll (seed pod) varied from 19 millimeters to 28.5 millimeters, a variation of 50 percent. This is very suggestive of the way by which, through a selection of parents, we have changed the cow so marvelously for milk production. The object of selection here is to find desirable strains that produce uniform progenies. It is fortunate that tree breeding has a more easily attainable objective -- namely, one good specimen.

Second, varying combinations in offspring of qualities of parents. A hybridization of hazels and filberts (Fig. 19) produced plants ranging from twelve inches to twelve feet in height -- suggestive of variations in great degree for each quality a plant can have.

Third, the appearance in hybrid offspring of qualities possessed by neither parent. Some of the above-mentioned hazel x filbert hybrids bore larger fruit than either parent. It is common for occasional plant hybrids to exceed either parent in speed of growth, size, earliness of fruiting.

Further experiments with cotton breeding show the dynamic and creative tendency of hybrids.

For experiments in breeding, the tree has one great advantage over most of the annuals. We propagate trees by twig or bud, by grafting or budding. Therefore, any wild, unstable (though useful) freak, any helpless malformation like the navel orange which cannot reproduce itself, can be made into a million trees by the nurseryman. The parent tree of the Red Delicious variety of apple grew, by chance, in an Iowa fence row. A representative of the Stark Nursery Company saw the apple at a fair and raced with all speed to the tree, bought it, and reproduced it by the million, an easy process if you really need a million trees. With corn, oats, or alfalfa, the breeder must produce a type true to seed before the farmer can use it.

Not only is the tree the great engine of production, but its present triumphant agricultural rivals, the grains, are really weaklings.

All plants require heat, light, moisture, and fertility. Give these things and the tree raises its head triumphantly and grows. But in addition to these requirements the weakling grains must have the plow. A given area may have rich soil and good climatic conditions, but be unsuitable for grain if the land happens to be rocky. Nor are steep lands good farm lands for grains. Trees are the natural crop plants for all such places.

Moreover the grains are annual plants. They must build themselves anew for each harvest. They may, therefore, become victims of the climatic peculiarities of a certain short season. It is rain in July that is so vital to the American corn crop. The rains of June cannot bring a good crop through. Also, if most of the rain due to fall in July happens to come in August, it comes too late. The corn has shot its bolt; it cannot be revived. Trees are much better able than the cereals to use rain when it comes.

They can store moisture much better than the annuals can store it, because they thrust their roots deep into the earth, seeking moisture far below the surface. They are able to survive drought better than the annual crops that grow beside them. For example, a drought that blasts corn or hay or potatoes may have little influence on the adjacent apple orchard. Trees living from year to year are a permanent institution, a going concern, ready to produce when their producing time comes.

Therefore, the crop-yielding tree offers the best medium for extending agriculture to hills, to steep places, to rocky places, and to the lands where rainfall is deficient. New trees yielding annual crops need to be created for use on these four types of land.

Two-story Agriculture for Level Land

The level plains where rainfall cannot carry soil away may continue to be the empires of the plow, although the development of two-story agriculture (trees above and annual crops below) offers interesting possibilities of a greater yield than can be had from a one-story agriculture.

This type of agriculture is actually in practice in many Mediterranean lands. In the Spanish island of Majorca I estimated as a result of several journeys across the island that nine-tenths of the cultivated land carries an annual crop growing beneath the tree crops. I recall a typical farm planted to figs in rows about forty feet apart. Beneath the fig trees was a regular rotation of wheat, clover, and chick-peas, one of the standard articles of Mediterranean nutrition. The clover stood two years and was pastured by sheep the second year.

Other two-story Majorca farms had, for a top crop, almonds, one of the staple exports of the island. Other lands were in olives, and a few were in the sweet acorn-bearing oak. The people said that the farmer did not get the greatest possible crop of wheat or the greatest possible crop of olives or figs, but that he got about a 75-percent crop of each, making a total of 150 percent. It is like the ship which fills three-fourths of her tonnage capacity with pig iron and five-sixths of her cubic capacity with light wood manufactures.

The two-story type of agriculture has another advantage. It divides the seasonal risks which everywhere beset the farmer. If frost kills the almond, it probably will not injure the wheat. If drought injures the wheat, the almond may come through with a bumper crop.

In some cases the Majorcan landlord rents the ground crops out to a tenant for a share and keeps all of the tree crops for himself, the tenant having contributed no labor in their production.

A Vision for our American Hills

We have large areas of hilly land where the climate is good. We have such an area of great beauty, with excellent climate and good soils, reaching from Maine to Alabama, from Alabama through Kentucky and Tennessee to central Ohio, from central Ohio through southern Indiana and Illinois into Missouri and Arkansas. Again, such an area appears on the foothills of the Rockies and the mountains of the Pacific Coast. Then too, there are hilly bits of land in nearly all sections of our country. When we develop an agriculture that fits this land, it will become an almost endless vista of green, crop-yielding trees. We will have plowed fields on the level hilltops and strip crops on the gentle slopes. The level valleys also will be plowed, but the steeper slopes will be productive through crop trees and will be protected by them -- a permanent form of agriculture. When we have done all this, posterity will have a chance. Under the trends of 1930 it had but little opportunity, and it is only a little better now. Good luck to the U. S. Soil Conservation Service!

Some Crops for the Hills

Chestnuts and acorns can, like corn, furnish carbohydrates for men or animals. To many it may seem ridiculous to suggest that we moderns should eat acorns, and I hasten to state that the chief objective of this book is to urge new foods for animals rather than for men. Food for animals is the chief objective of the American farmer. Our millions of four-footed brethren who bellow and neigh, bray and squeal, bleat and butt, eat much more than the two-footed population consumes. Their paunches receive the crop from about four-fifths of our farm acres.

When tree agriculture is established, chestnut and acorn orchards may produce great forage crops, and other orchards may be yielding persimmons or mulberries, crops which pigs, chickens, and turkeys will harvest by picking up their own food from the ground. Still other trees will be dropping their tons of beans to be made into bran substitute. Walnut, filbert, pecan, and other hickory trees will be giving us nuts for protein and fat food.

Even this partial list of native tree products, now producing in convincing quantity, shows nearly all of the elements necessary to man's nutrition save bulk, and for that we have leaf greens in plenty, and all that without introducing a single new species from foreign countries where dozens of new crop trees are waiting for the time to come when they can be made useful in American agriculture.

This permanent agriculture is much more productive than mere pasture, or mere forest, the only present safe uses for the hill fields. Therefore, tree crops should work their way into the rolling and sloping lands of all sections. New crop trees need to be created. Extensive scientific work at exploration and breeding in the plant kingdom should begin at once.

Doubling the Crop Area

As the deep-rooting, water-holding trees show their superior crop-producing power in dry lands, we may expect some of our now-arid lands to become planted with crop trees. Thus by using the dry land, the steep land, and the rocky land, we may be permitted to increase and possibly double our gross agricultural production and that, too, without resort to the Oriental miseries of intensive hand and hoe labor. Tree crops also have a special advantage in their adaptability to a field reservoir system of irrigation which is at the same time of great promise as a means of flood control. (See Chapter 22.)

The great question is, how can we shift from the grain type of agriculture and ruin to the permanent tree agriculture in those localities where the change is necessary to save the land from destruction? In the next chapter the attempt is made to find an answer to this question.

Fig. 2. Scene in the Carolina mountains showing stream now 100 yards wide, which once ran close to the hill at the right but is now destroying good meadow because of increased floods due to bare hillsides on its drainage basin. Note the steepness of the slope of the fields, the patch of corn at the right, and bad gullies above it. Cane Creek near Bakersville, N. C. (U. S. Forest Service.)

Next: 3. The Plan -- An Institute of Mountain Agriculture

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