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 eye 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 oiten 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 
