Method of IfcroHnaisNdHcc on the Rational Forests 77 



and compass, and kept the distance by pacing. There were 

 only one or two cases where chaining was used for more than 

 a mere check. The compassman also obtained elevations by 

 means of an aneroid barometer and sketched streams and 

 ridges on a field map, recording elevations in a note book, or 

 more commonly perhaps, sketching them as contours on the 

 field map. Types were outlined on the field map with colored 

 crayons by the compassman, and on one forest, age classes 

 were also mapped in. (In one case the estimator did the 

 type mapping instead of the compassman.) Topographical 

 maps were made on all the forests except one where a recent 

 dependable government survey made such maps unnecessary. 

 The contours used ranged from ten to one hundred feet, de- 

 pending on the character of the country. The compassman 

 in several cases aided the estimator in judging the forty 

 correction factor, in laying out sample plots to find the 

 amount of immature growth present, and in making the gen- 

 eral forest description. 



The estimators' duties were in general to estimate the 

 merchantable timber in D. B. H. classes and sixteen-foot logs. 

 In a recent Forest Service valuation survey in Virginia the 

 logs were recorded in different lengths varying with the spe- 

 cies, and in the case of one species the height of the tree was 

 recorded. Two-inch D. B. H. classes were used mostly while 

 one-inch classes were not uncommon in case of small timber. 

 On one forest the three-inch class was used. Ocular estimates 

 were made almost exclusively, although calipers and the 

 Biltmore stick were 'often used as checks. Calipering all of 

 the trees was exceptional. The estimates were kept separate 

 for the leading species by forties, and the minor species 

 grouped, although a few kept even the minor species separate. 

 The estimator determined the forty correction factor and also 

 a deduction percent for defects for each species on the forty. 

 Besides this estimation of merchantable timber he would 

 make an approximation of the immature growth present and 

 also write a description for each forty, although sometimes 

 only one description was made for a whole section. These 

 descriptions were a very important part of the reconnaissance 

 work and included -as some of the important points: (a) 

 Condition of the timber, whether an old decadent, mature, 

 or young stand ; whether fire injured, fungus injured, at- 



