SYSTEMS OF STRIP ESTIMATING IN USE 283 



In this system, as indicated in the last item, no effort was made to modify the 

 average stand per acre obtained from the strip in order to get a more correct total for 

 the area. The employment of inexperienced men made necessary the use of instru- 

 ments for diameter and height measurement, and the rigid elimination of the element 

 of judgment on every point possible. Where the unit of area was large, from 1 

 square mile up, this method gave excellent results, since the mechanical average for 

 areas of this size is quite dependable on the basis of a 5 to 10 per cent estimate. 

 The errors possible could be easily avoided by conscientious effort. These errors 

 consisted of too wide or narrow a strip, diameters measured too low, average heights 

 measured too high, dead trees calipered for live ones. When applied to large timber 

 in units of 40 acres or less, these mechanical results cannot be depended upon. 



Lake States Cruisers' Method 



Width of strip 8 to 10 rods — 2 to 2^ chains 



Number of strips per forty 1 to 2 



Per cent of area estimated 10 to 25 



Measurement of distances By pacing 



Measurement of trees Counted 



Heights Average number of 16-foot logs per tree 



Volume From number of logs on tract and log run, or 



contents of average log 



Forest types Timber of different age classes and quality 



separated 



Cull factor Usually by per cent deduction from total esti- 

 mate 



Corrections from strip estimate for 



average stand Close inspection of remaining area and modifi- 

 cation of average whenever necessary to 

 obtain correct total 



Of late, timber cruisers in these states have been adopting the use of volume 

 tables, but in many instances these tables are based upon stump diameter inside 

 the bark which makes them less consistent and accurate than if based on D.B.H. 

 The more modern cruisers are adopting the use of standard volume tables constructed 

 by regular methods and differentiated by D.B.H. and height. 



Southern Timber Cruisers' Methods 



Width of strip A strong tendency to substitute ocular esti- 

 mate, based on the stand per acre, for the 

 running of strips. Great carelessness in 

 methods until recently 



Measurement of distances Paced by a compassman, the cruiser usually 



riding a horse. Consequently estimates fre- 

 quently stopped at the edges of swamps 



Measurement of trees Cruiser gets located by compassman, but does 



not follow the strip. Trees are counted on 

 acre plots 



Volume of average tree Guessed at, using rule of thumb based on 



Doyle rule. Trees on entire forty may be 

 counted to check results of plots and get 

 reduction factor 



