The pruning of the pecan is neither difficult nor complicated. In short, after the top of the tree is well started, little need be done except to cut back a branch here and there that the trees may develop well-rounded, symmetrical tops. A splendid type of tree is shown in Plate VI.

High vs. Low-Headed Trees.

Frequently trees are so pruned that their first branches are eight or ten feet from the ground. Even young trees are pruned to slim stems, surmounted by a small umbrella-like top. Such trees frequently have to be tied to a post to keep them upright until such time as they attain sufficient size to support themselves. Such pruning should not be countenanced. The trees will make a much more rapid and satisfactory growth, and their trunks will be less affected by the hot sun, if the branches are allowed to develop lower down. Sometimes the system of pruning pecans with tall, bare trunks is adopted to allow of crops being grown under the trees, or because it is desired to use the ground as a cattle pasture. These considerations should not weigh against the welfare of the trees. As much ground can be cropped around low-headed trees as is good for them, and, in brief, the cows should be pastured elsewhere.

Ordinarily the top of the tree should be so shaped that the lower branches will be about four feet from the ground. The trunk will be shaded and protected, the crop will be nearer the ground, and the low tops will be less subject to the destructive force of heavy winds, so injurious to both fruit and branches.

To start the trees at four feet, the tops must be cut back to that height at the time the trees are set, or, if smaller, when they have grown to that height. Three or four buds nearest the top should then be allowed to develop and form the main framework of the tree. After this the trees will need little or no pruning, except the cutting back of straggling branches, and the removal of dead or broken ones.

Some writers have advised the persistent and severe cutting back of the tops, from time to time, so as to keep them small, compact and low, but such a system of pruning must be put into practice on a considerable scale for a number of years before it can be recommended. Such a plan might prove valuable where the trees are subject to the force of strong winds, but otherwise it is of doubtful value.

Time to Prune.

Pruning may be done at any convenient time, but the best period is probably either just before the flow of sap in spring, or just after the trees have fully developed their leaves in spring. Following the removal of branches of any considerable size—three-quarters of an inch and upward—the wounds should be carefully painted over with white lead paint to prevent decay.

Care of Broken Trees.

When trees are broken or injured by wind-storms, the broken branches should be cut off and the resulting wounds carefully trimmed and painted. If the branches are only partly split off, the injury may be repaired, in many cases, by pressing the branch back into place and bolting it there, so as to hold it firmly in place. Trees with forked trunks should be protected by passing a bolt through the two branches some distance above where they divide to prevent splitting.

Nursery Root-Pruning.

Too frequently the root system of pecan trees, intended for planting, is but poorly developed. The root consists almost entirely of one large taproot destitute of laterals. Such trees are slow in starting and are hard to transplant. Figure 33 shows an excellent root system on a nursery tree. Such a tree should be almost as easily transplanted as an apple tree. A little more care on the part of nurserymen would insure good root systems.

In a former publication it was suggested that the young seedlings intended for stocks be root-pruned "in the fall, after the trees are one year old. It could easily be accomplished by running the tree-digger down the row at a depth of nine or ten inches. The taproots could thus be severed, and the following spring, or summer, the trees could be worked (budded or grafted). This course of treatment would insure greater success in transplanting, as it would have a tendency to develop the lateral roots; and in addition to that, it would, in all probability, induce earlier fruiting."

Root Trimming Before Planting.

Two year old taproots should be cut to eighteen or twenty-four inches; larger ones, in proportion. The old idea that transplanted pecan trees, the taproots of which have been cut back, will not live and bear, is not borne out by experience. They are in no-wise injured by its partial removal, and it might all be removed were it not that so many would die in transplanting.

Figure 34 shows two pecan trees at two years. The one on the right was carefully lifted so as to preserve as much as possible of the taproot, while the one on the left had the taproot cut when it was transplanted at one year. In the latter, six small roots from four and one-half to eight inches in length had grown out to replace the taproot, these doubtless having supplied the tree with as much nourishment as would have been given by its single taproot. Furthermore, without doubt, one of these roots would have grown so as to replace the taproot.

The advice has been given to cut the taproots back to five or six inches, but under general average climatic conditions throughout the pecan region anyone who follows this advice will have reason to regret it. Our experience in transplanting pecan trees has been such as to indicate the necessity of having a well-branched, well-developed root system, and a taproot, when present, should be left at least as long as indicated above.

A long taproot is objectionable on account of the additional cost and labor entailed in digging holes of sufficient depth for planting. To shorten the length of the taproot, Mr. E. E. Risien, of San Saba, Tex., has patented a method which has given satisfactory results. The nuts from which the stocks are grown are planted over strips of mosquito netting, the netting being some distance below the level of the nuts. When the taproots have penetrated to the netting, their growth is stopped, and the lateral roots develop better in consequence.