August 25, 1921 



HARDWOOD RECORD 



19 



(4«*r*^*'\i 



1%. '^'■^'i^^^;»*''*-"*'ff*.' 



3,600, the number of seconds in 

 an hour. Factors affecting the 

 time of sawing are clearly re- 

 flected in rate of production |)or 

 hour. The white oak logs in ta- 

 ble 1, for I'.xaniple, show a steady 

 decrease in the rate of produc- 

 tion per hour as the diameter of 

 the logs increases, while the red 

 oak logs show an increase up to 

 26 inches in diameter and a 

 gradual decrease as the logs in- 

 crease in size above that diam- 

 eter. The effect of the time of 

 sawing for log classes for greon 

 and shipping-dry material is 

 shown in table 2. Because of 

 depreciation and shrinkage in 

 drying, the figures for the sliip- 

 ping-dry material are less than 

 for the material in the green condition. 



Time of sawing is of importance because it permits comput- 

 ing the cost of manufacturing a thousand fet of lumber, board 

 measure, from logs of any given diameter or group of logs. 

 The cost per thousand equals the number of seconds to saw the 

 average log multiplied by the average cost of manufacture per 

 second, divided by the lumber scale of the same log, and then mul- 

 tiplied by one thousand. The cost per thousand feet multiplied 

 by the net lumber tally produced per hour gives the cost of produc- 

 tion per hour. Because of shrinkage, development of defects, 

 etc., the cost for green and dry material will vary. 



Yield 



The lumber was graded according to the rules of the National 

 Hardwood Lumber Association by an official inspector of the asso- 

 ciation. The yield 



■;>,>*v<^Mj™.^^ 





table 2 are based on actual aver- 

 ages and not curves. In this 

 table "shipping dry" refers to 

 lumber air dried three months 

 during a winter in Arkansas. 



In general, the percentages of 

 plain-sawed white oak firsts and 

 seconds, and No. 1 and No. 2 

 common, decreased and the per- 

 centages of quarter-sawed mate- 

 rial for the same grades in- 

 creased as the diameters of the 

 logs increased. The percentages 

 of plain and quarter-sawed No. 

 ',\ common showed a steady de- 

 crease as the diameters of the 

 logs increased. 



As the diameters of the logs 

 iiici'('as<'d, the jiercentages of 

 both plain and quarter-sawed 

 red oak firsts and seconds increased; the percentages of plain-sawed 

 No. 1 common increased and then decreased a little, while the 

 quartered material steadily increased; the percentages of plain- 

 sawed No. 2 common decreased, and the quartered material in- 

 creased; and the percentages of plain and quarter-sawed No. 3 

 common showed a steady decrease. 



The effect of plain and quarter sawing, position in the tree, and 

 quality of logs on the jiercentages of the various grades is shown 

 in table 2. Sound logs, of course, produce better lumber than un- 

 sound logs, and butt logs a larger percentage of the better grades 

 than the middle and to]) logs for the same general run of trees. A 

 larger percentage of quartered material was produced in quarter 

 sawing than in plain sawing, but at an expense of an extremely 

 large percentage of waste and decrease in rate of production. 

 When the selling prices for the different grades are multiplied 



by the percent yield 



Common Means of Logging Oak During Wet 

 Delta Region 



season in 



net lumber tally 

 was plotted accord- 

 ing to diameters and 

 a curve drawn to 

 smooth out individ- 

 ual variations. Av- 



TABLE I 



Doyl* 90ftl* : 



»*t« '• Top 



lull 



1*1 - 



|»t tuBbar Tally 



r«T aont of •aoh ^ad* 



COBDOn 



-.flTtxm ftjid ■•oondu 

 .: risla :f^rt»*«d : ne. 1 Ro. £ |o. 3 



: : :PlBiD •od;- 



CrflffGS obtflintd ■ W«ln :qaart«r«d- Pl*l« :Qttu't*rtd'.qB*rtar«d 



from the curves for ; "• ; "■"; """ :""*"'"" ' 





the different diam- 

 eters of red and 

 white oak are shown 

 in table 1. The 

 average yield for 

 different groups of 

 logs is shown in 

 table 2. 



The percentage of 

 each grade of each 

 diameter was ob- 

 tained by dividing 

 the yield, net lum- 

 ber tally, of each 

 grade by the total 

 yield. These per- 

 centages were then 

 plotted and aver- 

 age curves drawn, 

 the results being 

 shown in table 1. 

 Percentages of the 

 various grades for 

 the different log 

 classes shown in 



« : % 



IT H I T E 



A E 



Pull 



Hat 



"■«""■ 



of these grades for 

 any iliameter or log 

 class and the prod- 

 ucts are added, the 

 sum represents the 

 average selling price 

 per thousand feet 

 net lumber tally. 



The average sell- 

 ing price per thou- 

 sand feet multiplied 

 by the net lumber 

 tally produced per 

 hour gives the gross 

 income per hour. 

 The income for 

 green or dry mate- 

 rial will vary ac- 

 cording to the 

 shrinkage, develop- 

 ment of defects, 

 variance in selling 

 price of green and 

 dry material, and 

 like factors. 



Appb'cation of Mill 

 Scale Data 



The summation of 

 the costs per thou- 

 sand feet net lum- 

 ber tally of stump- 

 age, logging, man- 



