~Changing Seedling Trees to Named Varieties~—On nearly every farm, walnut trees are growing along ravines, fence rows, and on rough land which is more or less out of the way and inaccessible. Most of these may be top-worked by one or more methods to the named and more desirable kinds of black walnuts without imparing the value of the timber. In 5 to 7 years seedling trees ranging in age from 15 to 40, if topworked, may produce crops equal to untreated trees. Still younger and smaller trees from one to 10 or 12 years old, may generally be top-worked with less difficulty than older trees.
~Results from Top-working Experiments~—Cleft grafting work performed at the Missouri Agricultural Experiment Station has been very successful. In fact, walnut top-working has been but little if any more difficult than apple or pear top-working. With reasonable care and fairly good technique the grafting operation is not difficult to perform. It is believed, however, that the common practice in top-working pecan, hickory, and walnut has been to dehorn too severely. This may induce insect and disease injury which often results in a very poor tree after 10 or 12 years. For good results, six inches in diameter should be the maximum size of the limb for top-working.
~Encourages New Industry~—A wider interest in black walnut kernels has caused a new industry to spring up. This consists of nut cracking or shelling establishments which have been located in the walnut growing districts. The plants in many instances buy walnuts in large quantities. The nut meats are removed and sold at wholesale, usually in barrel lots containing 180 pounds of nut meats. In most districts the new industry is in operation for most of the year.
Power driven machines feeding from large hoppers are used for cracking the nuts. Nearly all the workers pick the meats from the cracked nuts. Women are generally employed and are paid on a piece-work basis or by the pound. Moreover, employees are often given a premium for nut meats removed from the shells with the "halves" unbroken.
This new black walnut industry has increased and heightened the interest in planting the trees for both nut and timber production. Consequently, in the districts where these nut cracking mills have been established, many producers are planting either small or large blocks of black walnut trees. In some cases the plantings are made up of grafted or budded trees of named varieties, while in others the nuts are planted and the seedlings later top-worked to the kinds desired.
The named varieties and better seedling sorts bring the highest price in the form of nuts and as kernels. In fact, the nuts of the named varieties usually sell for twice the price paid for the average seedling nuts. Some of the chief varieties most highly prized for their thin shells, weight of kernels, cracking quality, and flavor are Thomas, Stabler, Tucker, Ohio, and Miller.
To obtain a marketable and paying product, care in the gathering, husking and extracting of kernels, is necessary. Culling the nuts and cracking none but the good ones are also important. Through such methods, many producers are able to supply city markets and roadside stands with kernels which sell readily and at good prices.
~Returns from Trees~—Walnut trees will give returns in general in proportion to the care given. They are fairly rapid growers under good culture. At an age of 20 years the trees may reach a height of 35 feet with 50 feet at 30 years and about 70 feet at 50 years. In other words, a growth of about 2 feet a year for 20 years is not unusual. After this age the trees slow down gradually to about a foot of growth a year.
It is estimated that walnut trees from 60 to 70 years of age will produce on the average from 100 to 150 board feet of lumber. Trees of such an age may also produce an average of all the way from four or five bushels of nuts per tree each year up to as many as ten to fourteen or more bushels per year.