BLACK WALNUT: ITS GROWTH AND MANAGEMENT. 

 Table 10. — The Doyle log rule. 



29 



Diam- 



Length in feel. 

























eter 

 in 



6 



7 



S 



9 



io 



11 



12 



13 



14 



15 



16 



inches. 



























Board feet. 



6 



1.5 



1.8 



2.0 



2.3 



2.5 



2.8 



3.0 



3.3 



3.5 



3.8 



4 



7 



3.4 



3.9 



4.5 



5.1 



5.6 



6.2 



6.8 



7.3 



7.9 



8.4 



9 



8 



6 



7 



8 



9 



10 



11 



12 



13 



14 



15 



16 



9 



9 



11 



12 



14 



16 



17 



19 



20 



22 



23 



25 



10 



13 



16 



18 



20 



22 



25 



27 



29 



31 



34 



36 



11 



18 



21 



24 



28 



31 



34 



37 



40 



43 



46 



49 



12 



24 



28 



32 



36 



40 



44 



48 



52 



56 



60 



64 



13 



30 



35 



40 



46 



51 



56 



61 



66 



71 



76 



81 



14 



37 



44 



50 



56 



62 



69 



75 



81 



87 



94 



100 



15 



45 



53 



60 



68 



76 



83 



91 



98 



106 



113 



121 



16 



54 



63 



72 



81 



90 



99 



108 



117 



126 



135 



144 



17 



63 



74 



84 



95 



106 



116 



127 



137 



148 



158 



169 



18 



73 



86 



98 



110 



122 



135 



147 



159 



171 



184 



-196 



19 



84 



98 



112 



127 



141 



155 



169 



183 



197 



211 



225 



20 



96 



112 



128 



144 



160 



176 



192 



208 



224 



240 



256 



21 



108 



126 



144 



163 



181 



199 



217 



235 



253 



271 



289 



22 



121 



142 



162 



182 



202 



223 



243 



263 



283 



304 



324 



23 



135 



158 



180 



203 



226 



248 



271 



293 



316 



338 



361 



24 



150 



175 



200 



225 



250 



275 



300 



325 



350 



375 



400 



25 



165 



193 



220 



248 



276 



303 



331 



358 



386 



413 



441 



26 



181 



212 



242 



272 



302 



333 



363 



393 



423 



454 



484 



27 



198 



231 



264 



298 



331 



364 



397 



430 



463 



496 



529 



28 



216 



252 



288 



324 



360 



396 



432 



468 



504 



540 



576 



29 



234 



273 



312 



352 



391 



430 



469 



508 



547 



586 



625 



30 



253 



296 



338 



380 



422 



465 



507 



549 



591 



634 



676 



31 



273 



319 



364 



410 



456 



501 



547 



592 



638 



683 



729 



32 



294 



343 



392 



441 



490 



539 



588 



637 



686 



735 



784 



33 



315 



368 



420 



473 



526 



578 



631 



683 



736 



788 



841 



34 



337 



394 



450 



506 



562 



619 



675 



731 



787 



844 



900 



35 



360 



420 



480 



541 



601 



661 



721 



781 



841 



901 



961 



36 



384 



448 



512 



576 



640 



704 



768 



832 



896 



960 



1,024 



37 



408 



476 



544 



613 



681 



749 



817 



885 



953 



1,021 



1,089 



38 



433 



506 



578 



650 



722 



795 



867 



939 



1,011 



1,084 



1,156 



39 



459 



536 



612 



689 



766 



842 



919 



995 



1,072 



1,148 



1,225 



40 



486 



567 



648 



729 



810 



891 



972 



1,053 



1,134 



1,215 



1,296 



forests, in which all or many of the species are to be logged together, 

 but by the separate examination of each merchantable tree. The 

 usual practice is to estimate first the length and small-end diameter 

 inside the bark of each log in the tree, and then to find the contents 

 of the logs in board feet by the Doyle rule. To estimate closely the 

 length and taper of the logs and their diameters inside the bark re- 

 quires a practiced eye and a knowledge of bark characteristics, in 

 order that the thickness may be gauged from appearances with rela- 

 tive accuracy. In most merchantable logs the bark averages from 1 

 to \\ inches in thickness, as shown in Table 11. 



Table 11. — Thickness of hark, in inches, on logs of different diameters. 1 



Diameter 



Bark 



Diameter 



Bark 



Diameter 



Bark 



of log. 



thickness. 



of log. 



thickness. 



of log. 



thickness. 



6 



0.5 



15 



1.1 



24 



1.3 



7 



.5 



16 



1.2 



25 



1.4 



8 



.6 



17 



1.2 



26 



1.4 



9 



.7 



18 



1.3 



27 



1.4 



10 



.8 



19 



1.3 



28 



1.4 



11 



.9 



20 



1.3 



29 



1.4 



12 



1.0 



21 



1.3 



30 



1.4 



13 



1.0 



22 



1.3 







14 



1.1 



23 



1.3 







1 Based on 291 logs mostly from Ohio and Indiana. 



