a) Physical form crossbar biltmore
Physical form crossbar biltmore form of rule by crutches at breast height (1.30 m) and has a scale (unit of measurement). Scale bar biltmore initially in the form of a hose diameter, has now been converted into units of measure. The units of measurement used is cm with the smallest unit of measurement in millimeters.
b) Basic Work
Note Figure 40 below.
Figure 40 How to use the bar biltmore
How to use the fork of the tree is:
(1) Align the top crossbar on the trunk.
(2) Scroll to the right and left until MBq is a straight line.
(3) The scale is read at S is the diameter of the rod.
c) Error measuring around a tree trunk
Trunk circumference measuring errors when using a fork of the tree is (Figure 41):
Figure 41. Error measuring with a ruler biltmore
Errors that occur when the position of the crossbar oblique (not parallel to the horizontal plane). Consequently lead to an error of:
Ed = B 1 S 1 – BS
with,
BS = position right tools
B 1 S 1 = notch wrong tool
a = the angle of the tool
Angle error is obtained from:
so,
BS = TB + TS
BS = (SO 1 x cos α) + (TS1 x cos α)
BS = (SO 1 + TS1) x cos α
then,
Ed = B1S1 – BS
Ed = B1S1 – (SO 1 + TS1) x cos α
Ed = B1S1 – B1S1 x cos α
Ed = B1S1 x (1 – cos α)