UNITED STATES DEPARTMENT OF AGRICULTURE 
MISCELLANEOUS PUBLICATION NO. 225 
July 1935 
Washington, D. C. 
CONVERTING FACTORS AND TABLES OF 
EQUIVALENTS USED IN FORESTRY 
Prepared in the Division of Silvical Research, Forest Service ! 
CONTENTS 
Page | Tables—Continued. Page 
Mao GUCHONVal: 2222 satese Ses See 2h ot 1 Ratios for customary map scales__-__-_____ 13 
TaO] OSS De ARR cee eta ep mal nen Sa anata alae Oiee 2 Scale of velocity equivalents of the 
Weenotits rte aes fe ere _2 2 Beaufort scale of wind_________________ 13 
LESTE RCE Co oie ee ee 3 Relative mumudily, =o 5 492 14 
Volume and capacity_____._____________- 3 Quartercirthyumitss: ss 2 See 15 
\WGIRAn pone So 2 Une ee kn ae ay Gk ae eae oa ee 4 Natural trigonometric functions_________ 15 
WELOOT Ny Se 2 kT RED Rone ATS eer ee men 4 International log rule!_— 222-222 16 
Tea ee ee eee | 5 Scribner decimal C log rule_________._____ 17 
Weight as applied to length______________ 5 Solid cubic contents of logs. _____________ 18 
Weight or pressure as applied to area____ 5 Comparison of log rules__________________ 19 
Weight as applied to volume___________. GMO ant Ge eee mcmin re bon ign sh ae Cente 21 
Volume of various units of weight of Temperature, figure 1___________________ 21 
CCl eee en es re ea he PN en ee 6 Wengthemeownresi2-3... = ss 23,25 
Weight of various units of volume of Areas neuresia jes’ fo eee et 27-33 
(WIIG ee ae ee 7 Volume, figures 8-10____________-________ 35-39 
Rainfall per unit area____________________ 7 AWieie lat efi ore ie e  ee 41 
Reservoir capacity_________ 5 Oa eats | Se 7 BOwer fewune gop 25.032 228.2 S 5 ee 43 
Discharge or flow of water______.________ 8 Wood volume, figure 13_________________ 45 
Approximate quantities of forest prod- Wood volume and basal area per unit of 
ucts represented by board foot measure_ 8 area, figures 14-15______________________ 47,49 
Approximate equivalents of forest prod- Weight and volume per unit of area, 
TCLS RIN sas | END eB See es on ced by 8 Newre iG {yy LL A) ee oe Se 51 
ATER OLSQUATES eee Ma 9 Volume per unit of area and weight per 
Area of small circles (basal area) ___--_-_- 10 unit of volume, figure 17_______________ 5 
Area of large circles_____________________- 12 Discharge or flow of water, figure 18____- 55 
Number of trees per acre_______________- 12 Value per unit of area, figure 19__________ 57 
Grades and slopes____.___..._._________- 12 Coefficients of correlation, figure 20______ 50 
INTRODUCTION 
The increasing use of metric measurements in the natural sciences 
is causing considerable confusion and difficulty in interpreting data. 
This is particularly marked in forestry where not only are direct 
measurements involved, but these measurements are also applied to 
different units of area. Thus while the conversion of centimeters to 
inches is a relatively simple matter, the conversion of board feet per 
acre to cubic meters per hectare is fraught with difficulties which are 
further increased when monetary values are involved. The purpose 
of this handbook is to provide members of the Forest Service with 
conversion factors and forest measurements that are more or less fre- 
quently encountered in forestry literature. These are expressed in 
tabular form where it appears most advantageous to do so; in the 
1 By E. N. Munns, assisted by Theresa (. Hoerner and V. A. Clements. 
12°035—35——1 1 
SSS 
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