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 ate 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." 



