TIMBER ESTIMATING. 67 



ever, one should use a whole acre, as the smaller area is less likely 

 to represent average conditions. 



Still another method is to count the trees in a narrow strip by 

 pacing off 10 yards, stopping and counting the trees for a distance 

 of 2 rods or 11 yards on each side; then pacing off another 10 yards, 

 again counting the trees, and so continuing until 55 yards have 

 been paced. The area covered, 165 by 66 feet, comprises an area 

 of one-quarter acre; or enough may be paced off to make a half or 

 a whole acre. 



There are several ways of estimating the volume of the average 

 trees in these methods of rough sample areas. Some estimate by 

 the ey^ the average yield per tree. Some estimate the average 

 number of logs per tree, and knowing, from the experience at the 

 local sawmills, the average contents of the logs, determines the 

 average yield of the standing trees. Another way is to select sev- 

 eral trees of average size, estimate their volume, and use the aver- 

 age of these as the average yield per tree in the forest. The best 

 that can be said about these methods is that in the hands of a man 

 with a great deal of local experience and opportunity to check 

 his results by seeing tracts which he has estimated actually cut, 

 he may often attain quite close results, provided he diligently 

 examines the entire area. But so great is the chance for error 

 that this so-called ocular estimating is no longer considered suf- 

 ficiently accurate. It is still used extensively, but with increas- 

 ing dissatisfaction. 



ESTIMATE BY INSPECTION OF EACH TREE. 



Most of the accurate methods of estimating used by cruisers in 

 this country are based on a counting or an inspection of every 

 merchantable tree. The simplest method, of course, is to count 

 the merchantable trees, and then to determine the volume of an 

 average tree and multiply this volume by the total number of 

 trees. 



In mountain districts where the land is rugged and there is 

 a constantly changing topography the merchantable trees may be 

 scattered as individuals or in small groups, and under these cir- 

 cumstances' it is comparatively easy to count the merchantable 

 trees without danger of duplication. If there is a possibility that 

 the trees may be counted more than once, each one when it is 



