, SOMETHING NEW IN HARDWOOD ICG GRADES January 1941 woe V A T i I IB. DOCUMENTS DEPT UNITED STATES DEPARTMENT OF AGRICULTURE FOREST SERVICE FOREST PRODUCTS LABORATORY Madison, Wisconsin In Cooperation with the University oi Wisconsin Digitized by the Internet Archive in 2013 http://archive.org/details/ewinhaOOfore SOMETHING NEW IN HARDWOOD LOG GRAi ■ 3y A. 0. 3EITS0N, Wood Technologist With the reduction of large holdings of virgin stands of timber and in turn the increasing necessity for lumber manufacturers to purchase their logs from scattered small holdings and farm woodlots, the matter of log grading is assuming a role of greater importance. Good logs are getting scarcer. Mills have been faced with the necessity of using a continually increasing propor- tion of poor logs. When logs are bought by the thousand feet instead of be- ing cut from the company's own lands there is a greater endeavor to make every dollar buy a dollar's worth of timber. How is the buyer to ascertain whether he is getting his money's worth? On the other hand, there is the seller's interest to consider. How is he to know that lie is getting what his logs are worth? Obviously, the answer is the same as the one that would be given for similar questions concerning transactions in lumber, cotton, wheat, and a host of other products, namely, through a grading system. There is a general recognition of this fact which is manifested by the increasing de- mand for some system that will enable group segregation of logs of like quality. Some lumbermen view log grading as simply another chore to be added to their already crowded routine. Still others view it as a necessity in a busi- ness that is becoming increasingly competitive. Upward trends of costs and greater demands in refinement of product without commensurate trends in prices of product are a combination that is resulting in survival only of the fittest. And the fittest are those who know their business down to the minutest details from raw material in the form of logs on through to the finished product. Log grading is not a new thought. Log quality classification of some sort has figured in log transactions for many years, but in hardwoods it has never made notable progress. Log grade specifications are little different now from those set up years ago. Although there has been some attempt on the part of regional organizations to secure adoption and general usage of stand- ard grade specifications little has come of such efforts, for the practice persists of each log buyer accepting logs based on his individual specifica- tions. Such specifications are generally unwritten ones, and the buyer is the sole interpreter of the quality classification. The practice is not without its advantages, for the user knows best the classes of logs that will meet his needs, but on the other hand there is no common meeting ground for buyer and seller so that lack of understanding is general and the seller is often left with a feeling that he might have done better if he had known more definitely what was in the buyer's mind. —Published in the Journal of Forestry, January 19^4-1 R1271 The Old Conception — Log Grades Based on Defects Attempts to grade logs have employed the principle of defects as a basis for quality classes, for it would appear obvious that logs with visible defects would be of poorer quality than those that were surface clear. The problem, therefore, has resolved itself into a matter of establishing degrees of permissible defect for certain quality classes; for instance, a No. 1 grade would admit few or no defects, a No . 2 grade would admit more defects, and a No. 3 grade still more defects. Such a system would be certain to re- sult in a rough quality stratification of lumber, but invariably the experi- ence has been that there has been too much overlapping among grades; that is, logs graded as No. 1 would often cut out a No. 2 grade and vice versa. The fallacy in the defect system of grading logs is that it is incon- sistent with the way hardwood lumber is graded. With limited exception, the specifications for the hardwood lumber grades make no reference to defects. They take their cue from hardwood lumber and the way it is used. About S5 percent of hardwood lumber is cut up before it is put in place in the final product -- chairs, tables, caskets, toys, and the like. For most uses the cuttings must be clear or at least clear on one side, on edges, and on ends. Consequently, the hardwood lumber grades are based on percentage of clear- face cuttings of specified minimum sizes. Does it not follow, then, that log grades should be based on some principle that recognizes the value of large defect-free areas instead of placing emphasis on number and size of defects and disregarding their location? Extreme difficulty is encountered in endeavoring to apply defect specifications. In order to simplify specifications to a reasonable degree it is necessary to establish a standard defect and translate the damaging effect of miscellaneous defects into terms of such standard. For instance, if a standard defect is stated to be a 3-inch knot, then cat face, bird pock areas, operating defects, and the many other common defects must be considered from the standpoint of their effect on quality of lumber in comparison with the lumber degrading effect of a- 3-inch knot. Except for the man who has spent a lifetime keenly observing logs being cut up and has formed definite ideas with respect to the damage caused by various types and sizes of defects, the comparative or equivalent principle is merely guesswork of the most hopeless kind. Very few men who are called upon to grade logs have had the opportunity to make adequate study of the way logs open up. It is necessary, therefore, to make the log grading system just as simple as possible consistent with reasonably accurate results. In this connection it is interesting to recall that in the process of evolution of hardwood lumber grades the grade of Firsts and Seconds, once determined on the basis of defects, was changed to a cutting grade. Students of hardwood lumber grades saw the need for greater simplicity and accuracy. Ten years of experience with the changed grade has proved the wisdom of con- centrating attention on cuttings instead of on defects. R1271 -2- The New Conception -- Log Grades Based on Defect-Free Areas Judging defect-free areas imposes no difficulties. Bark surface de- fects are subordinated and the problem becomes one of determining the size of the clear cutting area hetween defects. Thus, the main principle of grading hardwood lumber is used as the starting point for log grades. '.Then it came to application of this idea it was found advantageous to visualize the end surface of the logs as divided into quadrants with corresponding division of the bark surface into four sides or faces. Each face, then, could be surveyed independent of the others, and except for the curvature it would appeal- much as a piece of lumber. Going again to the lumber grades, it will be found chat the upper grades specify a certain high percentage of the surface must yield clear face cut- tings of a certain size or larger. Here again, are requirements that can be applied in principle when surveying the faces of the log. Naturally, all log grading systems strive to got a maximum yield of high-grade lumber in the highest log grade. By following the specifications for Firsts and Seconds hardwood lumber, the top grade, as closely as possible and incorporating them in the No. 1 log grade specifications it should be possible to group in this grade the logs that would yield a portion of their volume in Firsts and Seconds lumber. Similarly, the specifications for the lowur hardwood lumber grades could be followed for the lower log grades. By adopting this idea the Forest Products Laboratory has demonstrated by actual mill test that it is a practical procedure. It lias also been found that the tendency experi- enced in defect log grades for misallocation of logs is greatly reduced. In applying the log grade specifications it has been determined that requirements for the log are sufficiently realized if throe out of the four log faces make the grade. Time is thus saved and the grading procedure is simplified. Aside from the specifications built around cutting sizes and per- centages of yield, other grade controlling factors are introduced. The influence of size of log on value is recognized so that steps in sizes are set up, the higher the grade the groater the restriction on smaller logs. Interior log defect as indicated by defective end surfaces is taken into account. Maximum scale deductions on account of interior defect are specified independent of the quality as indicated by the bark surface. Crook and sweep are restricted. Stand ard Specificati ons t o Appl y to All Species and All Reg ion s Species vary one from the other within regions, and even a sir! ;] species may have characteristics in one region that are lacking in another region. Nevertheless, the work done thus far indicates that standard grade specifications may be made to apply regardless of species or region much the same as standard hardwood lumber grading rules are applied at R1271 .3. present. It will be necessary to provide modifications to take care of the peculiarities of certain species, but such details do not look too formidable . To date more than 1,000 logs of about 20 different species of northern hardwoods have been given detailed study by the Forest Products Laboratory, and the representation for this region is considered adequate. Field work will be extended to other regions. Specifications Based on Intensive Studies Field studies include diagramming log surfaces and getting lumber grade tallies for the individual logs. Subsequently the log diagrams can be used for trial of any log grade specification that might be up for consideration. The diagrams are virtually pictures of the log surfaces. All features that might affect the quality or quantity of yield are precisely positioned and described. The matching of log product with the information obtained from the diagram reveals the influence of type and extent of defect on quality and quantity of yield. Previous attempts to formulate log grades have not been based on de- tailed studies of this or any other kind. They have in the main resulted from some individual or group of individuals writing specifications based on the best judgment and experience that could be brought to bear. Under such methods faulty judgment would not be detected until the grading system was actually in use. Revision of specifications when- undertake it all has been a slow and uncertain process. The present approach seeks to anticipate the shortcomings of the specifications by what amounts to actual trial by means of the log diagrams. The new grading method being developed is not wholly something on paper, for it has been given trial by three log purchasing ogencies and no impractical features have come to light. It has also been used experimentally to grade logs in the standing tree, a procedure that will become increasingly important in making timber appraisals. At the present stage, however , no special research attention by the Forest Products Laboratory is being given to application of the log grades to trees. To formulate a log grading system is a matter sufficiently complicated without still further confusing it with tree grading however urgent may be the demand for the tree phase of the problem. RI271 -h- rtEGiGK JulltlV k UNIVERSITY OF FLORIDA Oct 3 ! 3 7PH'«II I! I 1 1 1 3 1262 08927 3337