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TIMBER ESTIMATING. 87 



Except on the very smallest areas, the dianieters of more than a 

 small portion of the timber are recorded but seldom, even in the 

 most accm-ate methods, and it is still more seldom that the height 

 of every tree will be recorded. 



A METHOD USED IX SOUTHERN YELLOW PIXE. 



A method used by the Yale Forest School in yellow pine is 

 intended to combine the advantage of counting the trees on a wide 

 strip with that of a tally of the heights of a large proportion of the 

 trees. Strips on compass lines are run across the tract, on which 

 the trees are counted to a width of 10 rods. Should the crew con- 

 sist of a compass man and two cruisers, each cruiser takes a 10-rod 

 strip on one side and parallel with the compass man. 



In this way 20 rods are covered, and two strips, one through the 

 center line of each half of 40 acres, will cover 50 per cent of the 

 entire area. In ordinary pine timber the cruiser can travel along 

 the outer or farther edge of his strip and thus view the timber out- 

 side of the strip, not counted. In hardwoods, swamps, or under- 

 brush, he takes the middle of the strip and counts to a distance of 

 5 rods on each side. 



One cruiser with a compass man could cover 20 rods in open 

 timber, but imder all conditions could be sure of only a 10-rod 

 strip, and working alone he could not cover more than 10 rods. 

 One man, or two, running 10-rod strips, would have to run four 

 strips per 40 to equal the accuracy of the double crew, but this 

 would seldom be done. Two strips of 10 rods would give 25 per 

 cent of the area. 



The compass man has the same opportunity to make a map and 

 take notes on the topography as he has in other strip systems of 

 estimating. The cruisers record their own tally and for volumes 

 depend on a volume table based on breast-high diameter and mer- 

 chantable 16-foot logs and half logs. The diameter and merchanta- 

 ble height of every tree on the strip might be tallied, but it was 

 found that equally accurate results were obtained on these wide 

 strips by tallying the dimensions of every fifth tree. In order to 

 avoid the tendency to select too large or small a tree for tallying, 

 it was the rule to tally each time the tree nearest the cruiser. 

 This tallying of 1 tree in 5 instead of every tree enables the crews 



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