PRACTICE OF TIMBER ESTIMATING 195 
estimate them separately, while on the other hand the 
area of bogs, burnt lands, barren mountain tops, etc., 
should be ascertained and thrown out of account. 
C. Summary 
The above described are well tried methods of timber 
estimating and survey, but what has been written affords 
hardly more than suggestions as to how any particular 
job may best be done. Each method has its merits which 
may strongly recommend it for some particular circum¬ 
stances. Very much too depends on the training and 
qualifications of the man doing the work. Every man 
long in the business commonly has a line of work in which 
he becomes proficient, developing methods best suited 
to himself to which in ordinary cases he will adhere. In 
conclusion, the following guiding principles may be laid 
down: 
1 . Estimates by lump sum are not usually reliable or 
at the present day sufficient. 
2. Estimates of so much to the acre are much easier 
to make and more likely to be close to the fact. 
3. In any kind of timber estimate or survey, the area 
of the land ought to be known, and that in units not too 
large. Within limits the smaller they are the better, all 
the more so if each unit contains but one timber type. 
4. Every time a measurement is substituted for a guess 
or judgment, the more reliable will be the result. On the 
other hand, experience and good judgment never cease 
to be required in the business. 
5. No estimate is worth much, practically speaking, 
which fails to take height into account as well as diameter. 
6 . Quality in some circumstances is quite as material to 
an adequate timber survey as quantity. Its determination 
is fully as difficult. 
7 . “The more defective the trees are, the more pref¬ 
erable is the cruiser’s judgment and long local experience 
in the mill and in the woods to mere measuring.” 1 The 
same is true where great differences in value are dependent 
upon quality or grade. 
1 Schenck’s “Forest Mensuration.” 
