"Frost Injuries to Apple and Pears," L. R. Jones (Vermont Sta. Bul. 49, p. 100, Fig. 1). (U. S. Exp. Sta. Rec. vol. VIII, p. 139). "Internal Frost Injuries," R. Hartig (Forstl. natur. Ztschr., 5 (1896), No. 12. pp. 483-488. Figs. 7. (U. S. Exp. Sta. Rec. vol. VIII, p. 471).

"Root-Killing of Fruit Trees," J. Craig, Canada Expt. Farm Rpt. 1896, pp. 147-153). U. S. Exp. Sta. Rec. vol. IX, p. 841).

"Report of Injury to Fruit Trees During the Winter of 1895-96," S. A. Beach and C. P. Close, New York State Rpt. 1896, pp. 408439). (U. S. Exp. Sta. Rec. vol. X. p. 251).

"A Report on Damage to Fruit Trees Caused by the Severe Freeze of November 26-28, 1896,” J. A. Balmer (Washington Sta. Bul. 30, p. 20). (U. S. Exp. Sta. Rec. vol. X. p. 550).

"Protection of Trees by Wrapping with Newspapers," Montana Sta. Bul. 16, pp. 82-89, S. M. Emery. (U. S. Exp. Sta. Rec. vol. XI. p. 251).

"Resistance of Blossoms of Different Varieties of Peaches to Frost," J. T. Bougue (Pacific Rural Press, 57 (1899). No. 24, p. 370). (U. S. Exp. Sta. Rec. vol. XI, p. 252).

"Winter-Killing of Fruit Trees," Monthly Weather Review, (U. S. Dept. Agr., Weather Bureau, 28 (1900). (U. S. Exp. Sta. Rec. vol. XII, p. 118).

"Observations and Suggestions on the Root-Killing of Fruit Trees," J. Craig, (Iowa Sta. Bul. 44, pp. 179-213, fig. 9.) (U. S. Exp. Sta. Rec. vol. XII, p. 147).

"Preventing Frost Injuries by Whitening." (Pacific Rural Press, 60 (1900). No. 18. p. 276), (U. S. Exp. Sta. Rec. vol. XII, p. 643). "Frost Injuries to the Winter Plantings of the Year 1901," P. Sorauer (Arb. Deut. Landw. Gesell., 1901, No. 62, pp. 8 x 205). (U. S. Exp. Sta. Rec. vol. XIII, p. 923).

"Early Spraying as a Means of Protection Against Spring Frosts," L. Degrully (Prog. Agr. et Vit. (Ed. L'est) 24. (1903) No. 9. pp. 257-258). (U. S. Exp. Sta. Rec. vol. XIV. p. 983).

"Spring Frosts and Fruit Trees," H. Muller-Thurgau (Ztschr. Pflanzenkrank., 10 (1900), pp. 335-340, figs. 3; abs. in Jour. Roy. Hort. Soc. (London) 26., (1901), No. 1. pp. 193-194). (U. S. Exp. Sta. Rec. vol. XIV, p. 46).

"The Effects of Frost Upon Forest Vegetation," R. G. Zon (Forestry Quart., 2 (1903), No. 1. pp. 14-21). U. S. Exp. Sta. Rec. vol. XV., p. 780).

"Spring Frost in the Mediterranean Climate," M. Chassant (Ann. Ecole, Nat. Agr. Montpillier, N. Ser., 2. (1903). No. 4, pp. 291323. pts. 6.) (U. S. Exp. Sta. Rec. vol. XV. p 232)

"Fruit Trees Frozen in 1904," M. B. Waite (U. S. Dept. Agr. Bureau of Plant Industry Bul. 51, pt. 3. p. 7). (U. S. Exp. Sta. Rec. vol. XV. p. 965).

"Plants and Frost," E. Vanderlinden (Ciel et Terre, 25 (1904), pp. 121-128). (U. S. Exp. Sta. Rec. vol. XVI. p. 649).

"Effects of the February Freeze of 1899 Upon Nurseries and Fruit Plantations in the Northwest," E. S. Goff (E. S. R. II, p. 930). (U. S. Exp. Sta. Rec. vol. XVI, p. 49).

"Fertility and Frost," U P. Hedrick (Michigan Farmer, 46, (1904) No. 20, p. 358. (U. S. Exp. Sta. Rec. vol. XVI. p. 447). "Frost Blisters and Their Origin," F. Noack (Ztschr. Pflanzenkrank, 15 (1905) No. 1. pp. 29-43. (U. S. Exp. Sta. Rec. vol. XVII, p. 777).

"Notes on the Effects of Frost on Trees at the Government Nursery, Irene," L. E. Taylor (Transvaal Agr. Jour. 4 (1906), No. 14. PP. 325-329). (U. S. Exp. Sta. Rec. vol. XVII, p. 1075.)

"Winter Injury to Fruit Trees," H. J. Eustace, New York State Sta. Bul. 269, pp. 323-343. pl. I). (U. S. Exp. Sta. Rec. vol. XVII, P. 558).

"The Relation of Early Maturity to Hardiness in Trees," R. A. Emerson (Nebraska Sta. Rpt. 1905, pp. 101-110, figs. 13). (U. S. Exp. Sta. Rec. vol. XVIII, p. 238).

"Experimental Studies on the Mechanical Effects of Frost on Fruit and Forest Trees," P. Sorauer (Landw. Jahrb., 35 (1906), No. 4. pp. 469-525, pls. 5). (U. S. Exp. Sta. Rec. vol. XVIII, P. 338).

"The Relation of Winter Apples to Hardiness of Trees," W. T. Macoun, (Canada. Hort., 29 (1906), No. 12, pp. 291-292, fig. I.). (U. S. Exp. Sta. Rec. vol. XVIII, p. 548).

"The Winter-Killing of Peach Buds as Influenced by Previous Treatment." W. H. Chandler (Missouri Sta. Bul. 74, p. 47, figs. 14). (U. S. Exp. Sta. Rec. vol. XIX, p. 237).

NOTES ON PRUNING.

By W. R. LAZENBY, Ohio State University, Columbus, Ohio.

I look back over a life, which I trust is not yet near its close, of nearly two score years of constant effort in the field of horticulture. While I cannot call it a misfortune, it sometimes comes tome as a more or less grievous disappointment that the exacting duties of a teacher have so fully employed my time and energies that I am a mere gobetween, a sort of middleman, and not a producer in the golden harvest field of horticultural science. It is a hope, rather than an expectation, that circumstances may yet put it in my power to give an undivided attention to the experimental solution of certain questions that perplex both the scientist and the fruit grower. Viewed in the retrospect, many of the questions which at times have claimed my interest, seem transitory and unimportant, although they loomed large in the time of their immediate presence.

Some things have been settled, and are well worth all the requisite effort by which accomplishment was secured. Other questions,

equally conducive to the progress of horticulture, have not been accorded the earnest consideration they deserve.

In an age when means of investigation are so generously provided, where every youth may be scientifically trained if he will, we have reason to expect fruitful harvests from the tree of knowledge. This increased harvest will not consist altogether or mainly in remarkable discoveries that will cause the fruit grower to at once double his yields, but in the gradual disclosure of the reasons of many things that we have long known or thought we knew. It will consist in the clear separation of what is true from what appears to be true, and will give in the place of wearying uncertainity, knowledge that is exact and positive. As investigators and teachers we are tempted to rest satisfied with the results of practice, without duly considering the real scientific basis upon which the practice should be founded. These and like reflections appeal to me with great force whenever I think of the subject of pruning.

Pruning is one of the essential operations in horticulture. Its objects are many and varied. It has been practiced in some form and to some degree ever since fruit plants have been grown. Much has been written and published on the subject, and various phases of the same have elicited spirited discussions at meetings of fruit growers. Yet in spite of its importance it is the one fundamental practice in horticulture about which we have little definite or exact knowledge, and still less well-grounded principles. Is it too much to say that less real progress has been made in the art of pruning during the past quarter of a century than in any other equally important branch of horticultural practice?

Certainly in the matter of selection of varieties, the question of the adaptability of soil and site, the laying out and planting, cultivation or management of soil, protection from insect enemies and fungous diseases, harvesting, storing and marketing, substantial progress has been made, and well-defined systems or policies have been quite generally adopted. On the other hand, with the possible exception of the grape, there are few definite or well-defined systems of pruning. It is a sort of hit or miss, go-as-you-please policy from start to finish.

If we ask why this lack of definite principles or widely accepted policies in pruning, the answer is, in part, the diverse not to say seemingly paradoxical object sought to be accomplished by the same operation. For example, we prune to stimulate as well as to check vigor of growth; to hasten as well as retard the age of bearing; to increase as well as decrease fruitfulness; to promote as well as restrain the production of wood, etc. If such directly opposite results are accomplished by pruning, the methods employed must be variable and the difficulties of the subject correspondingly great.

Again the answer may lie, in part, in the fact that we often fail to recognize the multiple individuality or colony character of our higher plants. We too often think of a tree as a distinct, definite

unity. We are prone to treat it as an individual with a complete anatomy like the higher forms of animal life. The fact is, a tree has no system of correlated definite organs, each performing some single function for the whole body. It has no well-defined span of life, for the organs by which it lives are usually renewed every year.

Every bud with its node is an individual, and is like both in structure and function, every other bud and node. Every leaf that comes from a bud is practically like every other leaf, and every absorbing root-hair is like every other root hair.

By removing a certain portion of the tree at one time we increase its vitality and enlarge its usefulness. By removing a like portion at another time we decrease its vitality and may still enlarge its

usefulness.

Such answers may partially explain our lack of progress and the chaotic condition of our knowledge regarding pruning. But they do not satisfy. Can it be that we cling to old forms and methods because it is easier and more popular than to search for truth? Why do we adhere to certain old practices until someone finds out they are absurd and preposterous, and we are forced to abandon them? Is it not a serious reflection upon horticultural science that the first real advance in tree surgery should be taken by a scientifically uneducated and untrained man? His enthusiasm and genuine love of trees impelled him to begin a work that should have been done by trained horticulturists years ago. While we cannot but admire the zeal of the man, who with some show of justice claims the title of "Father of Tree Surgery," we cannot but regret that his work is such a mixture of fact and fancy and such a jumble of sense and

nonsense.

Let us not repeat the mistake that medical science has made and is still making. By ignoring and holding itself aloof from "mental healing" or psychotherapy it incited and encouraged this branch of the healing art to evolve a scheme of its own, together with a system of religion that cannot be argued down.

The foundation may be faulty, the reasoning bad, but the intuitions are right, and we have an every-day working formula for health and happiness of which any school of medicine might well be proud.

Is it not time for our horticultural experts to get together and plan some far-reaching cooperative experiment in pruning?

We

Think of the questions to be settled. How little we know about the time to prune; how little about methods, and how little about results. Take the question of early maturity of apple trees. know that this is dependent not alone upon heredity, but upon environment as well. Can it not be controlled, in part, at least, by pruning?

Aside from our fruit plants the rejuvenation and prolongation of life of our native trees that have for generations beautified, ever

glorified the landscape, and have such a potent influence upon the aesthetic life, may well be considered.

The life of a veteran tree outside of the forest, at least, should be cherished with zealous care. What a contrast to the works of man. As we watch its growth there is no push and pull, no stress and strain, no grimy toil, no agony, no bloody sweat. It represents the calm, quiet, silent, persistent, resilient force of nature, acting through scores or even centuries of years. Yet, it can be destroyed in an hour, and when it is gone there is a vacancy not soon nor easily filled.

The time has come when more attention should be given to the dwarfing of trees by systematic pruning. As land becomes more and more valuable, and orchard areas more circumscribed, there will be a natural tendency to plant more closely. This will necessitate and impell to more radical pruning. We should be prepared for this.

Ten years ago the writer established a home on a vacant city lot. This lot was 75 x 160 feet, and devoid of tree or shrub. The question was how to have a comparatively spacious open lawn and a goodly number of trees, not excluding a fair proportion of shrubs, herbaceous perennials, and annuals. With some misgivings, and with the expectation of a speedy removal of at least two-thirds of the number, about two score trees were planted, some at considerable distance apart to form a border, others in close or compact groups, and quite a number at various points in close proximity to the house. Since that first planting many other trees have been added, and yet, by a more or less systematic pruning, all have been kept well within the allotted space. It was a revelation to me to learn that with slight but watchful care trees like the elm, sycamore. box elder, pin oak, basswood, silver maple, buckeye, hackberry, etc.. could be so easily dwarfed and at the same time retain their individuality in so marked a degree.

The result of the close group or compact planting was even more striking in mass and foliage effect. I have rarely if ever seen a more effective small group of shrubs or trees, or the two combined, than have been kept for many years at a height of from ten to twelve feet, and composed of the closely intermingled branches and foliage of the ailanthus, mulberry, honey locust, sassafras, coffee tree, sweet gum, white birch and willow. Of course the success of such planting depends mainly upon pruning, and how little we know of the kind of pruning that will give the best all-round results. It is certainly an interesting field for the landscape horticulturist.

My brief notes are ended. The object in view was to call attention to a sadly neglected area in the garden of scientific horticulture. Shall not this Society lend a hand in the inauguration and promotion of a series of investigations that will at least remove the stigma of farther neglect: