FOREST INSTRUMENTS. 147 
In practice these discrepancies are equalized as the result of 
the ordinary trade relations, and are not liable to work serious 
injustice under present conditions, and are here stated only to 
call attention to our crude methods of measuring timber. 
INSTRUMENTS USED IN FOREST MENSURATION. 
The Equipment of a Forester, while not extensive, must 
be complete for the work in hand. He surveys the land, lays 
out roads and ditches, cuts down trees and saws them into logs, 
measures diameters of logs and growing trees, takes heights of 
trees, determines rates of growth, estimates and measures tim- 
ber and cordwood, and maps and plats his work. Where there 
hhas been a survey of land by the government, as in this state, he 
will not be called upon to make one, as maps sufficiently reliable 
for his purpose may be had from official records; but to meet 
all the requirements of his position the forester should be an 
expert surveyor, and provided with all the necessary instruments 
for the work, including drawing instruments, tables, stationery, 
etc., for office work, in mapping and platting his field observa- 
tions. The work of forestry mensuration is concerned mainly 
with taking diameters and heights of trees, determining the areas 
on which they stand and the rate of growth. 
For Measuring Land Areas the ordinary steel tape, grad- 
uated on one side in feet, tenths and hundredths, and on the 
other side in links for convenience in computing acreage, is used 
—the 100-foot length being preferred. For the same purpose a 
steel chain is also used, and with the chain or tape should be a 
set of marking pins and ranging poles. In laying out small 
rectangular areas, as a sample acre, a cross-staff head, an angle 
mirror, or an angle prism is used; but for more extended sur- 
veys and for road and ditch work a transit and level would be 
advisable, while for the location of lost corners the magnetic 
compass might have to be resorted to. 
For the Rough Land Measurement of a Valuation 
Survey a Steel Chain, Thirty-three Feet Long, is used. 
This short chain is attached to a stout leather belt about the 
waist of the tallyman, whose hands are then free to carry the 
tallyboard holding notebook or tally blanks, and to work with a 
lead pencil. A small magnetic compass by which the tallyman 
directs his course is fixed on one corner of the tallyboard. 
