TABLE OF CONTENTS xiii 



PAGE 



195. The Principle of the Klaussner Hypsometer 236 



196. Methods Based on the Similarity of Right Triangles 238 



197. Hypsometers Based on the Pendulum or Plumb-bob 239 



198. The Principle of the Christen Hypsometer 243 



199. The Technique of Measuring Heights 245 



200. The Measurement of Upper Diameters. Dendrometers 247 



201. The Biltmore Pachymeter 248 



202. The d'Aboville Method for Determining Form Quotients 248 



203. The Jonson Form Point Method of Determining Form Classes 249 



204. Rules of Thumb for Estimating the Contents of Standing Trees 251 



CHAPTER XIX 



PRINCIPLES UNDERLYING THE ESTIMATION OF 

 STANDING TIMBER 



205. Factors Determining the Methods used in Timber Estimating 255 



206. Direct Ocular Estimate of Total Volume in Stand 256 



207. Actual Estimate or Measurement of the Dimensions of Every Tree of 



Merchantable Size 257 



208. Estimating a Part of the Timber as an Average of the Whole 257 



209. The Six Classes of Averages Employed in Timber Estimating 258 



210. The Choice of a System for Timber Estimating, with Relation to Accuracy 



of Results '. 261 



211. Relation between Size of Area Units and Per Cent of Area to be Estimated 262 



212. Degree of Uniformity of Stand as Affecting Methods Employed 265 



CHAPTER XX 

 METHODS OF TIMBER ESTIMATING 



213. The Importance of Area Determination in Timber Estimating 267 



214. The Forest Survey as Distinguished from Timber Estimating 268 



215. Timber Appraisal as Distinguished from Forest Survey 269 



216. Forest Surveying as a Part of the Forest Survey 270 



217. The Cull Factor, or Deductions for Defects 271 



218. Total, or 100 Per Cent Estimates 271 



219. Estimates Covering a Part of the Total Area. The Strip Method 273 



220. Factors Determining the Width of Strips 274 



221. Method of Running Strip Surveys. Record of Timber 276 



222. Tying in the Strips. The Base Line 281 



223. Systems of Strip Estimating in Use 282 



224. Methods Dependent on the Use of Plots, Systematically Spaced 285 



CHAPTER XXI 



METHODS OF IMPROVING THE ACCURACY OF TIMBER 

 ESTIMATES 



225. The Use of Forest Types in Estimating 288 



226. Method of Separating Areas of Different Types 290 



227. Site Classes and Average Heights of Timber 291 



