Appendix 



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Forest Survey Procedure 



Inventory 



The inventory o£ Kentucky's forest resources was 

 begun in May 1948 and completed in June 1951. 

 The volume data can be generally interpreted as 

 applying to the stands as they existed January 1, 

 1949. 



The amount of forest land in each county was 

 estimated from aerial photographs by a simple dot- 

 count method. Nearly 150,000 dots were counted 

 on the photos to get this preliminary estimate of 

 forest area. A photo interpreter examined about 

 12,500 of these stereoscopically. He classified the 

 acre of timber surrounding each dot by stand size 

 on the basis of tree height, crown width, and num- 

 ber of trees per acre. 



Finally, about 2,600 plots were selected to be 

 examined in the field. This selection was weighted— 

 the larger stand size classes were sampled more in- 

 tensively than the smaller. Crews of two men each 

 located and examined these plots on the ground. 

 They gathered such information as tree diameters, 

 merchantable heights, log grades, and amount of 

 cull. Each plot was 1/5-acre in area. 



In addition, nearly 700 plots classified as non- 

 forest on the photos were examined in the field to 

 check on changes in land use since the photos w'ere 

 taken. 



J'olume Tables 



Sawtimber volume.— The board-foot volume ta- 

 bles used in the Kentucky Forest Survey were based 

 on the Mesavage-Girard form class tables (-f). Aver- 

 age form classes were computed from estimates and 

 measurements on more than 2,000 trees, for 12-, 14-, 

 and 16-inch and larger diameter groups. Gross 

 cubic-foot tables were prepared from the Mesavage 

 cubic-foot form class tables. 



The volume for softwood upper stems was com- 

 puted directly from measurements of 30 trees. It 

 was found to average to 3 cubic feet per tree de- 

 pending on species and tree size. 



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PoLETiMBER VOLUME.— Diameters and merchant- 

 able height were measured on more than 1,200 pole 

 trees in the State. These estimates were summarized 

 by geographical units, by species, and by diameters 

 breast high. Average curves of merchantable height 

 over breast-high diameter were prepared and cubic- 

 foot volumes were computed by species and diam- 

 eters. 



Cull 



Trees of pole or saAvtimber size tliat did not 

 qualify as merchantable trees were tallied as cull 

 trees. The sound volume in these trees was not 

 included in the volume of gi'owing stock or in the 

 growth and drain estimates. 



In addition nearly every merchantable tree has 

 some cull volume. Field crews estimated both sound 

 and rotten board-foot cull in sawtimber trees. To 

 allow for unseen defects, the cull allowance was 

 adjusted in the various Forest Survey units accord- 

 ing to the recominendations of local foresters. Aver- 

 age cull factors were computed for gi'oups of spe- 

 cies having similar cull characteristics. 



A similar procedure was followed to adjust the 

 cubic-foot volumes. However, estimates of cubic- 

 foot cull in saw'timber trees alloAved for rotten 

 defects only. 



The cull percent for pole trees was assumed to 

 be the same as that for the smallest diameter saw- 

 timber trees of corresponding species. 



To determine the cubic volume of sound wood in 

 trees tallied as sound and rotten culls, the cull per- 

 cent in these trees was assumed to be the same as 

 used in Missouri and Illinois. Tw-enty percent of the 

 gross volume of sound cull trees was considered to 

 be rot, and in rotten cull trees the amount of rot was 

 estimated at 60 percent of the gross volume. 



Growth and Mortality 



Cores were taken from 4,622 sample trees and 

 growth for the past 10 years was measured. Growth 

 rates were computed by determining the ratio of 



36 



Forest Resource Report Xo. 7, U. S. Department of Agriculture 



