16 CIECULAE 3 3 3, U.S. DEPARTMENT OP AGEICULTUEE 



and densit} 7 of undergrowth. Under ordinary circumstances it serves 

 to signal through fairly heavy brush for about 200 feet. 



In forests containing much deciduous growth, the survey can be 

 made more easily after the leaves have fallen. 



Cutting of brush and undergrowth along survey lines should be 

 held to the minimum, and no other disturbance not made necessary 

 by the conditions of the experiment should be tolerated. 



Trees designating plot boundaries may be marked temporarily by 

 scratching blazes on the bark or by striking the trunk with a sack of 

 loosely woven material, such as a cotton sock, containing powdered 

 paint or chalk. In many cases it is preferable to outline the bounda- 

 ries temporarily with string. For this purpose a stout cord or 

 carpet twine serves satisfactorily. Such cord may be used later, 

 also, in dividing the plot. 



Blazing, scarring, or other defacing of trees in any stand should 

 be avoided unless it has a valid and clearly understood purpose ; pro- 

 miscuous blazing in connection with research projects is particularly 

 reprehensible. 



Trees on the line should be counted as within the plot if more 

 than half the diameter at the stump is inside the line. Where actual 

 w * line trees ", that is, trees the stems of which are at the time of plot 

 establishment exactly bisected by the line, are encountered, alternate 

 individuals should be considered " in " and " out ", with the invari- 

 able exception that line trees leaning into the plot should be con- 

 sidered " in " and line trees leaning out of the plot should be con- 

 sidered "out." Trees on the line should be so specifically and 

 clearly designated at the time of the survey as to inclusion or 

 exclusion that in future years no question will arise in this regard. 



The survey of a plot boundary should not be considered complete 

 until the error of closure has been determined and found to be 

 within the error previously decided upon as allowable. If the error 

 of closure is too large the survey must be repeated. 



Full and complete notes should be kept of all surveying in connec- 

 tion with plot establishment. These should record the date, the crew 

 personnel, the kind of instruments used, the error of closure, the 

 weather, and, if a compass is used, the magnetic declination. 



DIVIDING A PLOT 



Dividing a plot into sections, as has been mentioned, permits repli- 

 cation, makes it possible to arrange tree numbers systematically, and 

 facilitates the mapping of stems. Furthermore, division of a large 

 plot into a series of subplots in checkerboard fashion makes it pos- 

 sible to salvage a portion of the plot if some accident fatally disturbs 

 stand conditions on another portion. 



Any final plot division should be postponed until the survey of the 

 plot has been made to check. Ordinarily, however, while plot bound- 

 aries are being established division stakes or flags may be tempo- 

 rarily set along them. If the plot is rectangular and not too large, 

 such stakes should be set at regular intervals all around the bound- 

 ary and corresponding stakes on opposite sides of the plot then 

 connected with strings, which will divide the plot into rectangular 



