Introduction
Many growers of Chinese chestnut (Castanea mollissima) want to know how soon their young trees may be expected to bear their first crops of nuts. This is determined by several factors, but perhaps one of the most important is the amount and kind of pruning the trees receive during the first four or five years they are in the orchard. One reason for the importance of type of pruning is the characteristic habit of the species to form branches low on the trunk, so that low-headed and spreading tops result if trees are left unpruned.
It has long been accepted by most horticulturists that any kind of pruning of fruit trees tends to be a dwarfing process. Hence, pruned trees would be smaller than similar unpruned trees. Pruning of young fruit trees, though reducing the size of the top and the number of growing points, tends to stimulate the growth of the remaining shoots. This has a marked tendency to delay the formation of fruit buds. Hence, unpruned trees come into bearing earlier than even lightly pruned trees. Tufts (2)[3] reported that lightly pruned deciduous fruit trees, such as apple, pear, apricot, and peach, came into bearing one to three years earlier than similar trees that had been heavily pruned. Crane (1) found that height of head in apple trees had little effect on yield for the first nine years in the orchard, but at the time the experiment was terminated the trees were still too young for him to expect much fruit production. He found, however, that the low-headed trees made more shoot growth and a larger gain in trunk diameter than the high-headed ones, and thus the bearing area was larger. Because the tree form of the horticultural varieties of Chinese chestnut is somewhat comparable to that of apple varieties, it would be expected that the two might give similar growth and yield responses to pruning or training procedures. The experiment described in this paper was initiated for the purpose of determining the response made by trees of Chinese chestnut varieties pruned and trained to three heights of head.