MEASURING VOLUME Standing trees are assumed to be regular geometrical solids, resting on a circular base and tapering to the limbs, a compromise between a cone and a cylinder.
To get the solid contents of a trunk, the area of the base is multiplied by one-half the altitude. With a pair of calipers and any one of the four methods of obtaining the tree's height its cubical contents are easily computed. The forester cannot stop to multiply and compute the circular base on which the tree rests. He uses a table where these are worked out.
Timber is measured in board feet oftener than by volume. A board foot is a foot square and one inch thick; there are twelve board feet in one cubic foot. It is generally estimated that one third to one-half of a log is sawdust, slabs and defective wood. Allowance is therefore made for these losses. Much depends upon how the logs are sawed.
A "cruiser" was an old-time woodsman who went into the forest with a compass, and, pacing off the distances, located and estimated the timber in tracts with obscure boundaries. Once is was saw stuff only that he calculated. Now not only sawlogs, btt ties and poles and fuel are taken account of in these estimates.
By tables known as "Log Scales" the number of feet, board measure, a given tree will yield is quickly found. Height and diameter being known, the table gives the contents. In measuring standing timber it is customary for two measurers to go ahead and a tally keeper to record their work. Each tree is marked to
prevent counting it twice. Sheets for different kinds of trees and columns and lines for different heights and diameters of trees are provided in the record book. From this notebook and its tally marks the solid contents of a tract of woods is easily estimated at home or in the field, in terms of board measure or by cord measure. A cord is 128 cubic feet.
"Log scalers" or measurers record how many board feet a log will cut. These men carry a scale rule, which they apply to the small end of the log. From the diameter it measures four inches are deducted. The square of the balance is the log's contents in board feet, provided the length is sixteen feet. Allowance is made for logs longer or shorter than the standard. The table with these results worked out for logs from ten to sixty inches in diameter, and for twelve, fourteen and sixteen feet in length, constitute the Doyle-Scribner Log Scale in common use. It is a compact table, containing in four columns, of fifty lines depth, results that save much toilsome multiplying. It is so simple, however, that any intelligent woodchopper can reconstruct his own table in an evening, if he loses one. The four inches deducted allow for ordinary waste in sawing. Very crooked, knotty or otherwise defective logs have a greater deduction made at the discretion of the scaler.