In top-working old trees, only a portion of the branches should be worked at one time. If the whole top be removed at once, the tree suffers a severe shock. Two or three years are necessary to top-work a large tree, a half or a third of the top being worked each year. If the trees are of small size, the whole top may be removed at one time. CARE OF TOP-WORKED TREES. For several months after the new top has commenced to grow, the scions have but a slight hold upon the stock. The leaf surface is often so large that a slight wind may twist them off. To prevent this, a number of branches may be tied together, or they may be fastened to stubs of branches left temporarily. Posts may be driven into the ground close to the growing scions, to which they may be tied. Use soft bandages and burlaps. [Illustration: PLATE VII. An old Pecan tree Top-worked in the branches.] CHAPTER VIII. SOILS AND THEIR PREPARATION. The pecan succeeds on such a wide range of soils, that it is really easier to list those on which it should not be set than it is to enumerate those on which it may be planted. Of the soils not adapted to it, deep sandy lands, soils underlaid with quicksand close to the surface, soils with hardpan subsoil, wet, sour, poorly-drained lands, and stiff, pasty clays, may be mentioned particularly. If pecans are planted on land with a quicksand subsoil, the roots are unable to make their way downward through the quicksand. So far as being able to take a downward direction is concerned, they might as well be planted on top of a plate of metal. The writer once planted a few nuts on such a soil, to see what they would do. At the end of three years the tops were about two feet in height; the taproot, while thick and stocky, was not more than six inches long. It stopped abruptly after numerous efforts to penetrate the quicksand. In normally developed trees of the same age, the taproot would have been three or four feet long. The same objections hold against soils underlaid with a hard, impervious layer. While the pecan is at home on rich, alluvial river bottoms subject to overflow, yet it will not grow successfully on damp, soggy lands. It should not be planted on such soils unless they can be well drained, and not then until they have been limed and cultivated for some time to counteract the acidity of the land. We can definitely say that the pecan will do well on alluvial river bottoms, on sandy, loamy soils with a clay or sandy-clay foundation, on sandy-clay lands with clay predominating, on the flat woods sandy lands so common in the southeastern Gulf States, and on the higher uplands where hickory, dogwood, holly and oak abound. [Illustration: FIG. 26. Pecan Tree grown on quicksand. Note the taproot.] It is a fact worthy of note, however, that on extremely rich soils, the pecan will make wood growth at the expense of fruit, while on lands containing less fertility, less growth is developed with a proportionately large amount of fruit.