the predicted 10-year future volume to the present 

 volume of sample trees. These 10-year ratios w^ere 

 converted to annual compound interest rates and 

 then plotted over breast-high diameters for each 

 species. All formerly merchantable trees that died 

 within 4 years prior to the survey were tallied and 

 ratios of mortality to stand volume computed. 

 Growth and mortality percentages were applied to 

 volume to get net volume growth. 



Commodity Drain 



The commodity drain from Kentucky forests in 

 1948 was obtained by a sampling survey of wood- 

 product producers and wood users, and of logging 

 operations to determine the amount of logging 

 waste. 



Commodity drain of sawlogs was obtained by 

 sampling sawmills for lumber production. It was 

 assumed that exports of sawlogs equaled imports. 

 Lumber tally was converted to log volume, Inter- 

 national one-quarter-inch scale. 



Estimates of fuelwood, fence posts, and miscel- 

 laneous farm-timber production were based on area 

 sampling using the Master Sample of Agriculture. 



The production of round mine timbers was esti- 

 mated by multiplying the amount of wood used per 

 ton of coal produced by total number of tons pro- 

 duced. For the Eastern Coal Field the factor used 

 was 0.26 cubic feet of wood per ton of coal pro- 

 duced; it was derived from a Forest Service estimate 

 of the amount of wood used in eastern Kentucky 

 mines in 1942. For the Western Coal Field the fac- 

 tor used was 0.118 cubic feet per ton of coal pro- 

 duced; it was derived fiom a Forest Service study 

 of the amount of wood used by Illinois under- 

 ground mines. Cross-boundary drain was assumed 

 to be in balance. 



Production of all other commodities was based 

 upon a complete canvass of producers, concentra- 

 tors, or processors that might have used Kentucky 

 timber in the form of logs or bolts. Although nu- 

 merous inquiries were made, no production of 

 poles, piling, chemical wood, charcoal, or excelsior 

 wood was reported. 



Production was converted to drain by applying 

 factors derived from field studies of mill overrun, 

 distribution of trees cut, logging waste, and the pro- 

 portion of the product that came from upper stems, 

 limbs, saplings, and so on. 



Accuracy of Data 



Statistical analysis of forest area and timber vol- 

 ume data in Kentucky shows a sampling error of 

 drO.9 percent (d= 103.5 M acres) for commercial 

 forest area and of d=1.5 percent (±100.1 million 

 cubic feet) for growing stock volume. This means 

 that at one standard error, the chances are 2 out of 

 3 that the estimated area and volume would not 

 differ from the totals that would have been obtained 

 by 100 percent measurement by more than the 

 values shown. 



These estimates of sampling error do not include 

 errors resulting from the development and applica- 

 tion of volume tables and cull factors, or from mis- 

 takes in measurement or judgment. All phases of 

 field and office work were closely supervised to keep 

 these errors to a minimum. Since the percentage 

 error increases with each subdivision of the total, 

 small acreages or volumes may have large errors 

 and may therefore indicate only relative magni- 

 tudes. The following tabulation may be used as a 

 guide in estimating the probable sampling error 

 of the subdivisions of forest areas and volumes in 

 the tables: 



Commercial forest 



Growin 



g stock 



Sawtimber growing stock 



Area 



Sampling 

 error 



Volume 



Sampling 

 error 



Volume 



Sampling 

 error 



Thousand 





Million 





Million 





acres 



Percent 



cubic feet 



Percent 



board feet 



Percent 



11,446 



0.9 



6,570 



1.5 



U,6SS 



2 2 



5,000 



14 



5,000 



17 



20,000 



2.4 



1,000 



3.0 



1,000 



3.9 



10,000 



3.5 



500 



4,3 



100 



12.2 



1.000 



10 9 



50 



13.6 



10 



38.5 



100 



34.5 



10 



30.5 



1 



121 6 



10 



109.3 



Explanation of Terms Used 



Forest Land Classes 



Forest land area.— Includes (a) lands at least 10 

 percent stocked by trees of any size and capable of 

 producing timber or other wood products, or of ex- 

 erting an influence on the climate or on the water 

 regime; (b) land from which the trees described in 

 (a) have been removed to less than 10-percent stock- 

 ing and which has not been developed for other 

 use; (c) afforested area. 



Commercial forest land area. — Forest land 

 which is (a) producing, or physically capable of 



Kentucky's Forest Resources and Industries 



37 



