110 THE BOOK OF FORESTRY 
number of board feet be obtained and total measure- 
ments are rarely taken. 
Locating the Boundaries—Such a system requires a 
knowledge of the exact area in acres so if a map has 
not already been made, the boundary lines must be run 
and the area computed. These lines are generally run 
with a surveyor’s compass, since a transit requires too 
much clearing out of the line of sight to be easily used 
in forest surveying. 
If the boundary lines have not been run for many 
years, their retracing is a matter of great skill and 
one that requires much experience. The ax marks or 
blazes on the line trees have grown over; the corner 
trees with their markings may have been blown down cr 
burned, and it is only by exercising all the skill of a 
trained woodsman that many old lines can be located. 
For work of this sort, the aid of an expert should be 
secured, as he is accustomed to detecting the signs 
upon trees. If the lines have been run more than 
once it may be necessary to chop into the tree and see 
if the overgrown scar was made the correct number of 
years ago. If the correct survey was made in 1845 
and the lines are rerun in 1915, chopping down to the 
original scars should expose seventy rings. In this way 
the age of the survey is told. 
Strip Surveys.— After the boundaries have been located 
and well marked and the area has been computed, a start 
is made at a convenient point and parallel compass lines 
are ran back and forth across the tract equal distances 
apart and all the trees on a strip four rods wide, two 
rods on each side of the compass line, are measured. 
The diameter of the trees within this strip, whose width 
is largely obtained by the eye, are measured four and 
one-half feet from the ground with a pair of large cali- 
