according to the results produced. Improvement in the aggregate must be the sum of improvements at the individual mill; and at each mill a change must fit in with the individual conditions and prove itself as a part of the general practice before becoming established. The strong tendency is toward conservatism, toward continuing to do things according to established custom.

The first recommendation of the report is that the individual manufacturer undertake a program of tests of different methods in regard to foundations, pile widths, pile spacing, pile slant, direction of pile, height above ground, size of stickers, spacing of stickers, pile roofs, self-sticking, etc., and similar details in kiln-drying, with careful attention to the actual results secured, and modifying the established practice only as these tests show will be profitable. Such improvements should also be made public, if of such a character that they would probably be of value at other mills. The individual manufacturer should appreciate that any improvement would be of much more value to himself if adopted by the industry in general than if its use were restricted to his own mill, because the progress of the industry as a whole depends upon lumber as a whole being made better or more economical, and this is of more importance to every manufacturer than any narrow advantage which his own operation might have.

Such a manufacturer, of course, will be responsive to the results of field studies or tests by experts. If their results indicate the superiority of certain changes in established practice, an experiment on his own part along the same line will be indicated, and improvement in his own practice, if the results indicate that improvement, will be accomplished. In this way the practice of the industry can be brought in line with progressive research, with less lag and delay than has been the case in the past.

Individual research and experiment may be expected not merely to follow but in some cases to overtake and pass the results of expert research. Research has discovered conditions that manufacturers would have discovered for themselves had the subject received proper attention as a part of good practice in their everyday procedure.

The replies received show that at 27 of the reporting mills seasoning research has been carried on either by the association of which the mill is a member or by the United States Forest Service or its Forest Products Laboratory; in a few cases the work was done at some other mill but the reporting mill was in touch with the results and had derived benefit. A little over half the total mills reporting had made use of seasoning literature from the Forest Products Laboratory and had found it helpful, The Kiln-Drying Handbook, by Rolf Thelen, being most often mentioned as especially useful. This booklet has been revised and largely rewritten and is now in process of publication.

Another significant factor in the replies received is that 37 mills report having done a certain amount of experimental work on their own account on certain details of air seasoning or kiln-drying; and 34 report (and most of them describe) definite improvements that have resulted from these tests. This is encouraging because it includes more than half the total number of mills reporting; but it

seems obvious from a study of the replies that the mills where there is the greatest need for improvement are the ones that seem least likely to test improved methods wih a view to adopting them.

WHY THE MANUFACTURER SEASONS HIS LUMBER

The manufacturer has many reasons for seasoning the product that is to be shipped by rail. Incidentally, the all-important question of weights and freight must be taken into consideration, but the most important point is the demand on the part of the consumer for seasoned stock.

The buyers' wishes to that extent govern. They usually go further, however; the average buyer wants a certain degree of seasoning, and while different buyers may have somewhat different needs, the result is a composite which is the governing influence upon the manufacturer. A given degree of seasoning is found adequate by most of the buyers, and that is the seasoning for him to supply. Something less than that will bring complaints and restrict his volume of demand; something more will not create enough additional demand to be worth while. Unconsciously, in all probability, the degree of seasoning he gives has adjusted itself according to a law of economic average. Other factors have occasional effect on manufacturers' seasoning. In times of brisk demand lumber is grudged the time taken to airdry it and is sometimes shipped somewhat scant in seasoning, because there is an urgent order and no drier stock to fill it. The buyer may be a tacit party to this, having been informed of the situation by the manufacturer and responding with instructions to make the shipment.

Another factor which has exerted considerable influence on the seasoning of lumber, and more particularly in the common grades, is the increase in the loss through degrade. This occurs to a considerable degree in air-dried stocks that are carried in pile too long, and to even a more marked degree in kiln-drying. Formerly the sorting or separation for kiln-drying was a separation between thicknesses, or between saps and hearts, or between boards and strips, and common and uppers went into the kiln together and received the same thorough kiln-drying. In several leading softwood species this resulted in the development of so much degrade damage in the common lumber, by excessive checking and loosening of knots, that the loss in value far overbalanced the gain in freight saving through the reduced weight, where the lumber was to be shipped by rail. Much of the common is now separated and kiln-dried to a higher moisture content, sometimes 15 per cent but quite often 18 or 20 per cent; and a good deal of 2-inch common now leaves the kilns with a moisture content of up to 23 or 25 per cent. This stock probably has all the qualities of more thorough seasoned stock except that most of its shrinkage is yet to occur; and this may cause trouble because of the improper use of such material in building frames.

Manufacturers' seasoning may vary somewhat also in uniformity, because both air-dried and kiln-dried stock may come through with considerable variation in moisture distribution. In air-dried stock this results chiefly from taking the pile down too soon. In another 30 days the greener pieces would have completed their seasoning while the drier portions would have become little if any drier, and

thus an equalization would have been secured. If the manufacturer follows the practice of shipping lumber from piles which are mostly dry, or stock kiln-dried only to the desired stage in most of the stock, the exceptional pieces will not be dry enough for use, though the average of dryness and of shipping weight will be good.

This condition is probably responsible for most of the complaints of the last few years regarding seasoned condition of lumber when received. It seems to be evident that a reputation for good seasoning of his product and for uniformity of seasoning is an asset of distinct value to the lumber manufacturer, and that it can be secured by rigid control of his shipments and laying out of any occasional pieces which have not seasoned uniformly with the others.

The ineffective use of wood in building has not had the attention in the lumber industry that it needs, especially with regard to its seasoning; and the distributor, retailer, and contractor, along with the manufacturer, must share in the responsibility of furnishing a satisfactory product.

Seasonal influence is a rather serious matter in relation to air-dried stock. In any lumber section there are only about six months of the year during which the air-drying rate is satisfactorily rapid; during the other months it takes considerably longer to reach a satisfactory final condition, and in some sections during the winter months lumber already air-dried will pick up moisture instead of losing it, so that at such seasons it is not possible to supply lumber in as low a stage of moisture content as during the summer and early fall. This fact is the basis for one of the best arguments for the kiln-drying of lumber. Kiln-drying insures a uniform and dependable flow of seasoned lumber throughout the year, particularly in the fall, winter, and early spring months. Otherwise, sheds of enormous capacity in a fairly large operation would be required to house air-dried lumber taken from the piles during summer months and held for winter use. Mill tests of the moisture content of lumber ready for shipment have been made recently in all the manufacturing sections, and the results have been made known to the cooperating manufacturers, and the composite results for combined species have been published. The individual millman is therefore in a position to know whether the variation in seasoned condition of his own shipments is under the average range for his species and locality. The range of seasoning which is well tolerated by actual conditions of average use should be broad enough to enable the lumber manfacturer to keep within it. The cost of carrying seasoning effort to that extent is a very small addition to present seasoning costs in comparison with the results.

PLACE OF SEASONING IN AMERICAN LUMBER STANDARDS

It seems desirable to direct the attention of lumber manufacturers to two facts: (1) The quality of lumber for use depends upon its condition of seasoning quite as much as on grade or size and calls for standards of seasoning quite as directly as for standards of size and quality; (2) American Lumber Standards cover size and grade standards and have secured a fair uniformity of such standards in the various competing species, but there are still nowhere any official or recognized standards of seasoning.

The only principle now governing the seasoning of lumber is trade custom, very loosely defined as to most lumber product, and the terms of purchase contracts, though a surprisingly large proportion of such contracts do not adequately define the degree of seasoning desired. Common lumber moves as "air-dried" under various moisture contents from 12 to 25 per cent or more, and as "kiln-dried " under an even wider range of moisture content or from 6 to 25 per cent or more. In the upper grades of product both terms are a little more strictly defined, but a great deal of B and better "kiln-dried" ranges in moisture from 6 per cent to at least 20 per cent and with a small percentage of even higher moisture content.

There are a number of manufacturers who follow a more rigid practice, according to which good air-drying would be 18 per cent moisture content or under, and good kiln-drying as applied to the upper grades would be 6 to 10 per cent moisture content, the lower percentage being limited to stock for special uses such as flooring, sash and doors, and other factory product; most kiln-dried building lumber is sufficiently dry for use at 8 to 10 per cent.

There are lumber manufacturers who would object to any such seasoning requirements being set up as an official standard; indeed it is probable that there would be objections to setting 12 per cent as a maximum for kiln-drying and 25 per cent as a maximum for airdrying, because these manufacturers would find it difficult to bring their entire production below these maxima. At 25 per cent moisture content the average softwood species has not quite reached the point where shrinkage begins, except as surface drying may have gone a little further and produced some shrinkage. Many softwoods uniformly seasoned to 20 per cent have arrived at a fairly fit condition for common uses (not for finish and other high-grade uses), except in the matter of shrinkage. The 2-inch material which goes into house frames is now often seasoned little below that figure, and much of it above the figure, in order to reduce the degrade defects such as loosening of knots and checking, which more thorough seasoning would produce. The study by the Forest Products Laboratory of moisture content in material for shipment showed that in dimension, and taking all the species studied, 60 per cent of the material was at moisture contents ranging from 20 to 32 per cent, a little over half being between 20 and 24 per cent. (American Lumberman, April 21, 1927, p. 37.) The tests were mostly made during the winter season.

In other editions of the seasoning reports, those for the lumber consumer and the lumber distributor, this matter is discussed in more detail. The manufacturer does not come into direct contact with the field of small buildings; but if lumber manufacturers in general could bring influence to bear to secure a sounder use of wood in such buildings, the satisfaction of occupants would be increased and a tendency toward a larger use of wood would be created, and much of the complaint over "green lumber" would disappear.

The lumber industry is in need of standards of lumber seasoning comparable with standards already existing for size and grade, and for the same reasons that have been so effectively urged for those standards: (1) So that a given term defining seasoning will have a definite value in all competing species; (2) so that the buyer can choose the kind of seasoning that he wants and definitely specify it;

(3) so that the manufacturer may season his product to the three or perhaps four ranges of seasoning which will prepare it adequately for any general use within the entire range, knowing that this simplified seasoning will be acceptable and satisfactory.

At many of the official conferences on lumber standardization there have been received requests from the representatives of retail lumber merchants for the inclusion of definitions of seasoning in the American lumber standards.

Recently this agitation has resulted in a definite movement to standardize and define the moisture content in lumber. The central committee on lumber standards called a meeting early in 1928, in which resolutions were passed requesting the consulting committee on lumber standards to consider and formulate recommendations from the various lumber manufacturers' associations, dealing with dryness specifications as a basis for the measurement of American lumber standard sizes and the definition of lumber dryness. Recommendations for revising American Standards for Structural Materials were requested, also. The necessity for this type of information caused the general conference of lumber producers, distributors, and consumers held in Washington, D. C., to decide unanimously to support this movement, and that such recommendations should be submitted by lumber manufacturers' associations to the central committee on lumber standards not later than November 1, 1928.

The definition of lumber moisture content, so stated as to meet all and every condition, is a problem almost incapable of solution. Each of the regional associations has its own particular problems, which are entirely different from each other. Physical properties of the species, of the wood-manufacturing problem, the handling, seasoning, and care of lumber, together with entirely different seasonal conditions, are only a few of the many complexities which must be solved before such a definition can be established. With this thought in mind, the consulting committee on lumber standards met in Chicago November 19 and 20, 1928, to discuss ways and means of solving this problem. Some of the ablest authorities on these matters decided, after the most careful investigation and discussion, that a solution in regard to a definite understanding of moisture content in lumber could only be handled by the various regional associations themselves. The standard definition applying a standard measure of moisture content was not practicable, and if such a proper value could be established there would be considerable difficulty encountered by the various regional associations, to whom such a definition would not be practicable. It was finally decided that each of the regional associations should establish among themselves a standard and definition for moisture content, as applied to their particular species, this definition pertaining specifically to air-dried and kiln-dried stock. At last a progressive step has been taken, a logical step, that will establish a definite understanding between the producer, distributor, and consumer of forest products regarding the definition of standard lumber dryness applied to a particular kind and species of wood. With such an understanding there is no doubt that industry will have made a valuable movement toward comprehending the relationship of the fabricated product and its moisture content.