To a certain extent the ability of orchard trees to withstand frost injury is subject to control. The danger is greatest with trees which have grown late or those which have become devitalized for some reason or with those which are in poorly drained soils. The kind of root stock which has been used, is known to have had an influence in some cases. Doubtless this will be better understood as different stocks are used by the leaders in pecan breeding. Varieties also are known to differ greatly in their degree of hardiness. However, failure upon the part of otherwise normal trees to bear paying crops with regularity is not necessarily due to low temperatures. Other factors, such as self-sterility, may be wholly responsible for at least the lightness of crops. So far as the orchardist is concerned, a tree is not hardy unless it is capable of bearing crops the average of which are profitable. On the other hand, occasional winter injury does not prove that a species cannot be grown successfully in the same locality. Neither the peach nor the apple industries of the North nor those of the citrus in the South and California nor, in fact, any of the other horticultural commodities of this country are wholly unaffected by frost damage. Our forest trees may be more subject to winter killing than we suspect. A certain amount of winter-injury is to be expected in any part of the country no matter what the species of plant may be. The frequency with which winter or spring injury is definitely known to occur gives color to a rising theory that freezing temperatures may play a vastly greater part in the development of the nut industry over the entire country than is commonly supposed. Much of the evidence of damage from this cause is of such nature as to be easily overlooked or attributed to other causes. Trees and plants of many kinds have become so accustomed to injury by freezing that they are able to recover without the injury always being apparent. A few illustrations of this which have come to the writer's attention might be cited.