journals and by the publication of special monographs and books on local horticultural subjects.1

In the development of fruit industries, California has had notable help from other states through the placing of fruit products under the protective tariff. This offsets remoteness, higher cost of transportation and higher wages than ever paid in the Mediterranean countries which were her chief competitors. The handicap which impended through the free trade legislation of 1913 was averted by the world war and the revenue needs of the country after the war may render indulgence in free trade policies impracticable for a long time.

In acknowledging California's great debt to national help in population, capitalization and legislation, it is not amiss to remember that she has achieved. results which have had distinct bearing on the fruit development of the whole country, a few of which may be cited.

First, the relation of tillage to thrift and productiveness of fruit-trees and vines. California demonstrated that clean garden-like culture of large fruit areas is superior to cow-pasture conditions; and first applied on a large scale the principle that adequate

1 The scientific and technical literature of California fruitgrowing is considerable, not only in the publications of the State Boards mentioned but in those of the U. S. Dept. Agr. and of the Calif. Agr. Exp. Sta. There are also comprehensive treatises viz., "California Fruits and How to Grow Them" by E. J. Wickson; "Citrus Fruits" by J. E. Coit; "Standard Cyclopedia of Horticulture," by L. H. Bailey, has descriptions of California methods in the treatments of all leading fruits and ornamental plants, as well as descriptive and botanical characterization of forest trees, etc.; "Manual of Tropical and Subtropical Fruits" by Wilson Popenoe.

tillage is effective for moisture conservation, both in operations by rainfall and by irrigation, as will be outlined in Chapter VIII. To these early conceptions, the State has recently added the widest demonstration that cover-cropping with tillage includes restoration of soil fertility in the act of securing the highest duty of water.

Second, the relation of form to efficiency of plant performance. Methods and styles of tree and vine pruning have been devised and older systems from other parts of the world modified with such success that "California style" is recognized horticulturally and accepted as a model for imitation in more recently developed fruit regions in all parts of the world. "California style" in pruning is, however, progressive and is undergoing modification as the result of improvements demonstrated by research and large operations in practice.

Third, the relation of plant protection to success in commercial production. California has devised. original methods and demonstrated the value of new materials in insect warfare which other fruit-growing countries have accepted as important improvements. In addition to her initiative in legislation to control and exclude pests, she first applied highpressure spraying and invented devices to secure it; first publicly announced through an experiment station bulletin investigations which made legal control of insecticide manufacture and sale imperative, although a few other states preceded in actual enactments; first demonstrated the efficiency of lime sul

fide in killing armored scales on dormant deciduous trees, which is now universally employed for that purpose; discovered the availability of hydrocyanic gas for insect killing on tented evergreen trees and saved her citrus industry by systematic and timely invention which rendered the use of this treatment practicable and profitable; first made great and striking demonstration of success in bringing from abroad the natural enemy of an injurious insect which arrested the latter's progress and made world search for beneficial insects and introduction of them a sustained State policy. In a very different phase of fruit protection, California was first to demonstrate the feasibility of frost prevention by direct heating of the atmosphere.

Fourth, the relation of new varieties to commercial fruit production. New varieties of fruits have been originated, which, in the case of peaches, plums, almonds and walnuts, constitute the larger part of the commercial product; the immense citrus fruit production has been built up with varieties of especial suitability which were not commercially important elsewhere. All these fruits of California birth and adoption have now a place in the world pomologies and are becoming important abroad in all regions which have natural conditions resembling our own. In addition to his notable contributions to this attainment, the unique conceptions and original methods of Luther Burbank have given California popular repute for leadership in plant-breeding and have stimulated public interest in plant improvement.

However, in fruit-growing California does not need new varieties so much as better ones of types already demonstrated to be supremely serviceable and acceptable. In this direction, the demonstration of rigid test and acute selections as a basis of propagation made in California seems destined to become a moving horticultural force throughout the world.

Fifth, the relation of enterprises and methods to fruit preservation. California is the leading state in the Union in the output of canned and dried fruits, and her styles of these products and methods of producing them are models in other parts of the world which have conditions favoring their use. The pioneer policy of producing fruits directly for preservation as a primary product and not looking on preservative processes as merely means for saving fruits from waste, was new to America though it was a prevailing practice in some parts of Europe. On it rests largely the development of great canning and drying industries. The California drying tray is an original invention of about fifty years ago, which by its cleanliness, ease of handling and economy of space, immediately relieved producers from most of the cost and dirt of the drying floors used from time immemorial throughout the Mediterranean region. The use of sulfur for preserving natural color in sun-dried fruit is an ennobling of the older art of using sulfur as a bleaching agent.

The California fruit box, so-called, but which was probably first used in shipping Oregon apples to San

Francisco, threatens to displace the old bushel basket and barrel, as fruit carriers everywhere.

California raisin machinery has invaded historic Malaga. Packing-houses for all kinds of fruit embody original work in plan, policy and appliances, and the remarkable results attained in careful handling of fruit in the orchard, on the road, in the packing-house and in the cars, and in realizing the advantage of pre-cooling.

California grows many fruits of the temperate and semi-tropical classes. The list is growing and some are coming into prominence and acreage which are not yet enumerated by the official statisticians, while many others receive attention only from enthusiastic amateurs. It is not the design of this writing even to approach the categories of kinds and cultures but merely to cite facts enough about particular fruits to indicate to the general reader the materials and conditions that enter into the pursuit of the greatest agricultural industry of California and thus underlie the greatest fraction of the rural life and industry of the State.

The fruits that are commercially great in California, and their relative importance, are concretely shown by the State Board of Equalization, on the first of March 1920, in the table on page 178.1

As it is the function of the State Board of Equalization to deal with taxation and as their enumerators are the county assessors, securing their data

1 The amount and value of the 1920 product of these plantations, also the movement beyond State lines and the quantities of preserved fruit products are given in Appendices G and H.